2006-10-22 Akira TAGOH <at@gclab.org>

	* hieroglyph/Makefile.am (libhieroglyph_la_SOURCES): added hglog.c.

	* hieroglyph/hglog.[ch]: new files for logger.

35 files changed, 594 insertions, 276 deletions

diff --git a/ChangeLog b/ChangeLog
index 7ae1bd3..cf3d5c0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2006-10-22  Akira TAGOH  <at@gclab.org>
+
+	* hieroglyph/Makefile.am (libhieroglyph_la_SOURCES): added hglog.c.
+
+	* hieroglyph/hglog.[ch]: new files for logger.
+
 2006-10-21  Akira TAGOH  <at@gclab.org>
 
 	* hieroglyph/vm.c (_hg_vm_op_rollbacksecuritylevel): ignore the errors.
diff --git a/devices/cairo/cairo-ps-main.c b/devices/cairo/cairo-ps-main.c
index 0c75071..32412d2 100644
--- a/devices/cairo/cairo-ps-main.c
+++ b/devices/cairo/cairo-ps-main.c
@@ -1,7 +1,7 @@
 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
 /* 
  * cairo-ps-main.c
- * Copyright (C) 2005 Akira TAGOH
+ * Copyright (C) 2005,2006 Akira TAGOH
  * 
  * Authors:
  *   Akira TAGOH  <at@gclab.org>
@@ -29,6 +29,7 @@
 #include <cairo/cairo-ps.h>
 #include <glib.h>
 #include <hieroglyph/debug.h>
+#include <hieroglyph/hglog.h>
 #include "hgdevice-cairo.h"
 
 
@@ -62,7 +63,7 @@ device_open(HgPageInfo *info)
 
 	fd = g_file_open_tmp("ps-embedded-XXXXXX", &filename, NULL);
 	if (fd == -1) {
-		g_warning("Failed to open a file descriptor.");
+		hg_log_warning("Failed to open a file descriptor.");
 		if (filename)
 			g_free(filename);
 
@@ -80,7 +81,7 @@ device_open(HgPageInfo *info)
 	cdev->u.ps.fd = fd;
 
 	if (cairo_status(cdev->reference) != CAIRO_STATUS_SUCCESS) {
-		g_warning("Failed to create an reference of cairo.");
+		hg_log_warning("Failed to create an reference of cairo.");
 	}
 
 	TRACE_LEAVE;
diff --git a/devices/cairo/cairo-xlib-main.c b/devices/cairo/cairo-xlib-main.c
index 29dfe5a..c08e4a4 100644
--- a/devices/cairo/cairo-xlib-main.c
+++ b/devices/cairo/cairo-xlib-main.c
@@ -26,6 +26,7 @@
 #endif
 
 #include <cairo/cairo-xlib.h>
+#include <hieroglyph/hglog.h>
 #include "hgdevice-cairo.h"
 
 
@@ -44,7 +45,7 @@ _cairo_xlib_real_set_page_size(HgCairoDevice *device,
 		      width, height);
 	cairo_xlib_surface_set_size(device->surface, width, height);
 	XFlush(device->u.xlib.dpy);
-	g_warning("%s: FIXME: implement me", __FUNCTION__);
+	hg_log_warning("%s: FIXME: implement me", __FUNCTION__);
 
 	return TRUE;
 }
@@ -68,7 +69,7 @@ device_open(void)
 	cdev->u.type = HG_DEVICE_CAIRO_XLIB_SURFACE;
 	cdev->u.xlib.dpy = XOpenDisplay(NULL);
 	if (cdev->u.xlib.dpy == NULL) {
-		g_warning("Failed to open a display.");
+		hg_log_warning("Failed to open a display.");
 		hg_device_destroy(dev);
 		return NULL;
 	}
@@ -89,7 +90,7 @@ device_open(void)
 						  400, 400);
 	cdev->reference = cairo_create(cdev->surface);
 	if (cairo_status(cdev->reference) != CAIRO_STATUS_SUCCESS) {
-		g_warning("Failed to create an reference of cairo.");
+		hg_log_warning("Failed to create an reference of cairo.");
 		hg_device_destroy(dev);
 		return NULL;
 	}
diff --git a/devices/cairo/hgdevice-cairo.c b/devices/cairo/hgdevice-cairo.c
index 0761761..c8fbcee 100644
--- a/devices/cairo/hgdevice-cairo.c
+++ b/devices/cairo/hgdevice-cairo.c
@@ -26,6 +26,7 @@
 #endif
 
 #include <hieroglyph/hgarray.h>
+#include <hieroglyph/hglog.h>
 #include <hieroglyph/hgvaluenode.h>
 #include "hgdevice-cairo.h"
 
@@ -85,7 +86,7 @@ _hg_cairo_device_print_path(HgPathNode    *node)
 				    g_print("%f %f %f %f %f %f curveto\n", node->x, node->y, node->next->x, node->next->y, node->next->next->x, node->next->next->y);
 				    node = node->next->next;
 			    } else {
-				    g_warning("[BUG] Invalid path for curve.");
+				    hg_log_warning("[BUG] Invalid path for curve.");
 			    }
 			    break;
 		    case HG_PATH_ARC:
@@ -93,7 +94,7 @@ _hg_cairo_device_print_path(HgPathNode    *node)
 				    g_print("%f %f %f %f %f arc\n", node->x, node->y, node->next->x, node->next->next->x, node->next->next->y);
 				    node = node->next->next;
 			    } else {
-				    g_warning("[BUG] Invalid path for arc.");
+				    hg_log_warning("[BUG] Invalid path for arc.");
 			    }
 			    break;
 		    case HG_PATH_MATRIX:
@@ -101,11 +102,11 @@ _hg_cairo_device_print_path(HgPathNode    *node)
 				    g_print("[%f %f %f %f %f %f] matrix\n", node->x, node->y, node->next->x, node->next->y, node->next->next->x, node->next->next->y);
 				    node = node->next->next;
 			    } else {
-				    g_warning("[BUG] Invalid matrix was given.");
+				    hg_log_warning("[BUG] Invalid matrix was given.");
 			    }
 			    break;
 		    default:
-			    g_warning("[BUG] Unknown path type %d was given.", node->type);
+			    hg_log_warning("[BUG] Unknown path type %d was given.", node->type);
 			    break;
 		}
 		node = node->next;
@@ -244,7 +245,7 @@ _hg_cairo_device_real_finalize(HgDevice *device)
 {
 	HgCairoDevice *cdev = (HgCairoDevice *)device;
 
-	g_warning("%s: FIXME: implement me.", __FUNCTION__);
+	hg_log_warning("%s: FIXME: implement me.", __FUNCTION__);
 	cairo_show_page(cdev->reference);
 	XFlush(cdev->u.xlib.dpy);
 
@@ -361,8 +362,8 @@ _hg_cairo_device_real_stroke(HgDevice       *device,
 		} else if (HG_IS_VALUE_REAL (node)) {
 			d = HG_VALUE_GET_REAL (node);
 		} else {
-			g_warning("[BUG] Invalid object type %d was given for dashline pattern.",
-				  HG_VALUE_GET_VALUE_TYPE (node));
+			hg_log_warning("[BUG] Invalid object type %d was given for dashline pattern.",
+				       HG_VALUE_GET_VALUE_TYPE (node));
 			d = 0.0;
 		}
 		dashes[i] = d;
@@ -421,7 +422,7 @@ _hg_cairo_device_set_path(HgCairoDevice *device,
 						   node->next->next->x, node->next->next->y);
 				    node = node->next->next;
 			    } else {
-				    g_warning("[BUG] Invalid path for curve.");
+				    hg_log_warning("[BUG] Invalid path for curve.");
 				    retval = FALSE;
 			    }
 			    break;
@@ -432,7 +433,7 @@ _hg_cairo_device_set_path(HgCairoDevice *device,
 					      node->next->next->x, node->next->next->y);
 				    node = node->next->next;
 			    } else {
-				    g_warning("[BUG] Invalid path for arc.");
+				    hg_log_warning("[BUG] Invalid path for arc.");
 				    retval = FALSE;
 			    }
 			    break;
@@ -449,12 +450,12 @@ _hg_cairo_device_set_path(HgCairoDevice *device,
 				    cairo_set_matrix(device->reference, &trans);
 				    node = node->next->next;
 			    } else {
-				    g_warning("[BUG] Invalid matrix was given.");
+				    hg_log_warning("[BUG] Invalid matrix was given.");
 				    retval = FALSE;
 			    }
 			    break;
 		    default:
-			    g_warning("[BUG] Unknown path type %d was given.", node->type);
+			    hg_log_warning("[BUG] Unknown path type %d was given.", node->type);
 			    retval = FALSE;
 			    break;
 		}
@@ -481,7 +482,7 @@ _hg_cairo_device_set_line_cap(HgCairoDevice *device,
 		    cap = CAIRO_LINE_CAP_SQUARE;
 		    break;
 	    default:
-		    g_warning("[BUG] Invalid linecap type %d", line_cap);
+		    hg_log_warning("[BUG] Invalid linecap type %d", line_cap);
 		    cap = CAIRO_LINE_CAP_BUTT;
 		    break;
 	}
@@ -505,7 +506,7 @@ _hg_cairo_device_set_line_join(HgCairoDevice *device,
 		    join = CAIRO_LINE_JOIN_BEVEL;
 		    break;
 	    default:
-		    g_warning("[BUG] Invalid linejoin type %d", line_join);
+		    hg_log_warning("[BUG] Invalid linejoin type %d", line_join);
 		    join = CAIRO_LINE_JOIN_MITER;
 		    break;
 	}
diff --git a/hieroglyph/Makefile.am b/hieroglyph/Makefile.am
index 88433ed..1d259db 100644
--- a/hieroglyph/Makefile.am
+++ b/hieroglyph/Makefile.am
@@ -46,6 +46,7 @@ hginclude_HEADERS =						\
 	hggraphics.h						\
 	hglineedit.h						\
 	hglist.h						\
+	hglog.h							\
 	hgmacros.h						\
 	hgmatrix.h						\
 	hgmem.h							\
@@ -95,6 +96,7 @@ libhieroglyph_la_SOURCES =					\
 	hggraphics.c						\
 	hglineedit.c						\
 	hglist.c						\
+	hglog.c							\
 	hgmatrix.c						\
 	hgmem.c							\
 	hgpage.c						\
diff --git a/hieroglyph/hgallocator-bfit.c b/hieroglyph/hgallocator-bfit.c
index 4385e91..4ed8f91 100644
--- a/hieroglyph/hgallocator-bfit.c
+++ b/hieroglyph/hgallocator-bfit.c
@@ -29,6 +29,7 @@
 #include <setjmp.h>
 #include "hgallocator-bfit.h"
 #include "hgallocator-private.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "ibtree.h"
 #include "ilist.h"
@@ -194,14 +195,14 @@ _hg_allocator_bfit_remove_block(HgAllocatorBFitPrivate *priv,
 						       HG_MEM_ALIGNMENT,
 						       aligned);
 	if ((l = hg_btree_find(priv->free_block_tree, GSIZE_TO_POINTER (aligned))) == NULL) {
-		g_warning("[BUG] there are no memory chunks sized %" G_GSIZE_FORMAT " (aligned size: %" G_GSIZE_FORMAT ".\n",
-			  block->length, aligned);
+		hg_log_warning("[BUG] there are no memory chunks sized %" G_GSIZE_FORMAT " (aligned size: %" G_GSIZE_FORMAT ".\n",
+			       block->length, aligned);
 	} else {
 		HgListIter iter = hg_list_find_iter(l, block);
 
 		if (iter == NULL) {
-			g_warning("[BUG] can't find a memory block %p (size: %" G_GSIZE_FORMAT ", aligned size: %" G_GSIZE_FORMAT ".\n",
-				  block, block->length, aligned);
+			hg_log_warning("[BUG] can't find a memory block %p (size: %" G_GSIZE_FORMAT ", aligned size: %" G_GSIZE_FORMAT ".\n",
+				       block, block->length, aligned);
 		} else {
 			l = hg_list_iter_delete_link(iter);
 			if (l == NULL) {
@@ -236,7 +237,7 @@ _hg_allocator_bfit_add_free_block(HgAllocatorBFitPrivate *priv,
 		HgMemBFitBlock *b = block->prev;
 
 		if (((gsize)b->heap_fragment + b->length) != (gsize)block->heap_fragment) {
-			g_warning("[BUG] wrong block chain detected. (block: %p heap: %p length: %" G_GSIZE_FORMAT ") is chained from (block: %p heap: %p length: %" G_GSIZE_FORMAT ")", block, block->heap_fragment, block->length, b, b->heap_fragment, b->length);
+			hg_log_warning("[BUG] wrong block chain detected. (block: %p heap: %p length: %" G_GSIZE_FORMAT ") is chained from (block: %p heap: %p length: %" G_GSIZE_FORMAT ")", block, block->heap_fragment, block->length, b, b->heap_fragment, b->length);
 			break;
 		}
 		/* block must be removed from array because available size is increased. */
@@ -253,7 +254,7 @@ _hg_allocator_bfit_add_free_block(HgAllocatorBFitPrivate *priv,
 		HgMemBFitBlock *b = block->next;
 
 		if (((gsize)block->heap_fragment + block->length) != (gsize)b->heap_fragment) {
-			g_warning("[BUG] wrong block chain detected. (block: %p heap: %p length: %" G_GSIZE_FORMAT ") is chained to (block: %p heap: %p length: %" G_GSIZE_FORMAT ")", block, block->heap_fragment, block->length, b, b->heap_fragment, b->length);
+			hg_log_warning("[BUG] wrong block chain detected. (block: %p heap: %p length: %" G_GSIZE_FORMAT ") is chained to (block: %p heap: %p length: %" G_GSIZE_FORMAT ")", block, block->heap_fragment, block->length, b, b->heap_fragment, b->length);
 			break;
 		}
 		/* it could be merged now */
@@ -591,17 +592,17 @@ _hg_allocator_bfit_real_free(HgMemPool *pool,
 
 	hg_mem_get_object__inline(data, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Unknown object %p is going to be destroyed.", data);
+		hg_log_warning("[BUG] Unknown object %p is going to be destroyed.", data);
 		return;
 	}
 	block = obj->subid;
 	if (block == NULL) {
-		g_warning("[BUG] Broken object %p is going to be destroyed.", data);
+		hg_log_warning("[BUG] Broken object %p is going to be destroyed.", data);
 		return;
 	}
 	if (hg_btree_find(priv->obj2block_tree, block->heap_fragment) == NULL) {
-		g_warning("[BUG] Failed to remove an object %p (block: %p) from list.",
-			  data, block);
+		hg_log_warning("[BUG] Failed to remove an object %p (block: %p) from list.",
+			       data, block);
 		return;
 	}
 	hg_btree_remove(priv->obj2block_tree, block->heap_fragment);
@@ -681,7 +682,7 @@ _hg_allocator_bfit_real_resize(HgMemObject *object,
 		HgAllocatorBFitPrivate *priv = pool->allocator->private;
 
 		if (block == NULL) {
-			g_warning("Failed to allocate a block for resizing.");
+			hg_log_warning("Failed to allocate a block for resizing.");
 			return NULL;
 		}
 		block->prev = blk;
@@ -815,7 +816,7 @@ _hg_allocator_bfit_real_gc_mark(HgMemPool *pool)
 		for (list = pool->root_node; list != NULL; list = g_list_next(list)) {
 			hg_mem_get_object__inline(list->data, obj);
 			if (obj == NULL) {
-				g_warning("[BUG] Invalid object %p is in the root node.", list->data);
+				hg_log_warning("[BUG] Invalid object %p is in the root node.", list->data);
 			} else {
 				if (!hg_mem_is_gc_mark__inline(obj)) {
 					hg_mem_gc_mark__inline(obj);
@@ -921,7 +922,7 @@ _hg_allocator_bfit_real_save_snapshot(HgMemPool *pool)
 	retval = hg_mem_alloc_with_flags(pool, sizeof (HgMemSnapshot),
 					 HG_FL_HGOBJECT | HG_FL_COMPLEX);
 	if (retval == NULL) {
-		g_warning("Failed to allocate a memory for snapshot.");
+		hg_log_warning("Failed to allocate a memory for snapshot.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -1010,7 +1011,7 @@ _hg_allocator_bfit_snapshot_real_set_flags(gpointer data,
 			obj = chunk->heap_chunks;
 
 			if (!HG_CHECK_MAGIC_CODE (obj, HG_MEM_HEADER)) {
-				g_warning("[BUG] Invalid object %p to be marked in snapshot.", obj);
+				hg_log_warning("[BUG] Invalid object %p to be marked in snapshot.", obj);
 			} else {
 				if (!hg_mem_is_flags__inline(obj, flags))
 					hg_mem_add_flags__inline(obj, flags, TRUE);
diff --git a/hieroglyph/hgarray.c b/hieroglyph/hgarray.c
index 459f128..0e3cda0 100644
--- a/hieroglyph/hgarray.c
+++ b/hieroglyph/hgarray.c
@@ -29,6 +29,7 @@
 #include "hgarray.h"
 #include "hgstring.h"
 #include "hgbtree.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hgvaluenode.h"
 #include "hgfile.h"
@@ -83,7 +84,7 @@ _hg_array_real_set_flags(gpointer data,
 	if (array->name) {
 		hg_mem_get_object__inline(array->name, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: Array name", array->name);
+			hg_log_warning("[BUG] Invalid object %p to be marked: Array name", array->name);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -92,7 +93,7 @@ _hg_array_real_set_flags(gpointer data,
 	for (i = 0; i < array->n_arrays; i++) {
 		hg_mem_get_object__inline(array->current[i], obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: Array %d", array->current[i], i);
+			hg_log_warning("[BUG] Invalid object %p to be marked: Array %d", array->current[i], i);
 		} else {
 #ifdef DEBUG_GC
 			G_STMT_START {
@@ -112,7 +113,7 @@ _hg_array_real_set_flags(gpointer data,
 	if (array->arrays) {
 		hg_mem_get_object__inline(array->arrays, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: Array", array->arrays);
+			hg_log_warning("[BUG] Invalid object %p to be marked: Array", array->arrays);
 		} else {
 #ifdef DEBUG_GC
 			G_STMT_START {
@@ -164,7 +165,7 @@ _hg_array_real_dup(gpointer data)
 
 	retval = hg_array_new(obj->pool, array->n_arrays);
 	if (retval == NULL) {
-		g_warning("Failed to duplicate an array.");
+		hg_log_warning("Failed to duplicate an array.");
 		return NULL;
 	}
 	memcpy(retval->arrays, array->current, sizeof (HgValueNode *) * array->n_arrays);
@@ -188,13 +189,13 @@ _hg_array_real_copy(gpointer data)
 
 	if (hg_mem_is_copying(obj)) {
 		/* circular reference happened. */
-		g_warning("Circular reference happened in %p (mem: %p). copying entire object is impossible.", data, obj);
+		hg_log_warning("Circular reference happened in %p (mem: %p). copying entire object is impossible.", data, obj);
 		return array;
 	}
 	hg_mem_set_copying(obj);
 	retval = hg_array_new(obj->pool, array->n_arrays);
 	if (retval == NULL) {
-		g_warning("Failed to copy an array.");
+		hg_log_warning("Failed to copy an array.");
 		hg_mem_unset_copying(obj);
 		return NULL;
 	}
@@ -345,7 +346,7 @@ hg_array_append_forcibly(HgArray     *array,
 
 	if (!force) {
 		if (!hg_mem_pool_is_own_object(obj->pool, node)) {
-			g_warning("node %p isn't allocated from a pool %s\n", node, hg_mem_pool_get_name(obj->pool));
+			hg_log_warning("node %p isn't allocated from a pool %s\n", node, hg_mem_pool_get_name(obj->pool));
 
 			return FALSE;
 		}
@@ -367,7 +368,7 @@ hg_array_append_forcibly(HgArray     *array,
 					   sizeof (HgValueNode *) * (array->allocated_arrays + HG_ARRAY_ALLOC_SIZE));
 
 		if (p == NULL) {
-			g_warning("Failed to resize an array.");
+			hg_log_warning("Failed to resize an array.");
 			return FALSE;
 		} else {
 			array->current = array->arrays = p;
@@ -412,7 +413,7 @@ hg_array_replace_forcibly(HgArray     *array,
 
 	if (!force) {
 		if (!hg_mem_pool_is_own_object(obj->pool, node)) {
-			g_warning("node %p isn't allocated from a pool %s\n", node, hg_mem_pool_get_name(obj->pool));
+			hg_log_warning("node %p isn't allocated from a pool %s\n", node, hg_mem_pool_get_name(obj->pool));
 
 			return FALSE;
 		}
@@ -489,7 +490,7 @@ hg_array_fix_array_size(HgArray *array)
 		}
 		p = hg_mem_resize(array->arrays, sizeof (gpointer) * array->n_arrays);
 		if (p == NULL) {
-			g_warning("Failed to resize an array.");
+			hg_log_warning("Failed to resize an array.");
 			return FALSE;
 		}
 		array->current = array->arrays = p;
diff --git a/hieroglyph/hgbtree.c b/hieroglyph/hgbtree.c
index cbe73a2..3e07ed1 100644
--- a/hieroglyph/hgbtree.c
+++ b/hieroglyph/hgbtree.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "hgbtree.h"
+#include "hglog.h"
 #include "hgmem.h"
 
 
@@ -131,8 +132,8 @@ _hg_btree_page_real_set_flags(gpointer data,
 	if (page->key) {
 		hg_mem_get_object__inline(page->key, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgBTreePage key",
-				  page->key);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgBTreePage key",
+				       page->key);
 		} else {
 			hg_mem_add_flags__inline(obj, flags, TRUE);
 		}
@@ -140,21 +141,21 @@ _hg_btree_page_real_set_flags(gpointer data,
 	if (page->val) {
 		hg_mem_get_object__inline(page->val, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgBTreePage val",
-				  page->val);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgBTreePage val",
+				       page->val);
 		} else {
 			hg_mem_add_flags__inline(obj, flags, TRUE);
 		}
 	}
 	if (page->page == NULL && page->n_data > 0) {
-		g_warning("[BUG] HgBTree structure corruption. no real data, but it says there are %d item(s).",
-			  page->n_data);
+		hg_log_warning("[BUG] HgBTree structure corruption. no real data, but it says there are %d item(s).",
+			       page->n_data);
 	}
 	if (page->page) {
 		hg_mem_get_object__inline(page->page, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgBTreePage page",
-				  page->page);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgBTreePage page",
+				       page->page);
 		} else {
 			hg_mem_add_flags__inline(obj, flags, TRUE);
 		}
@@ -167,16 +168,16 @@ _hg_btree_page_real_set_flags(gpointer data,
 			if (page->page[i]) {
 				hg_mem_get_object__inline(page->page[i], obj);
 				if (obj == NULL) {
-					g_warning("[BUG] Invalid object %p to be marked: HgBTreePage page[%d]",
-						  page->page[i], i);
+					hg_log_warning("[BUG] Invalid object %p to be marked: HgBTreePage page[%d]",
+						       page->page[i], i);
 				} else {
 					hg_mem_add_flags__inline(obj, flags, TRUE);
 				}
 			}
 			hg_mem_get_object__inline(page->val[i], obj);
 			if (obj == NULL) {
-				g_warning("[BUG] Invalid object %p to be marked: HgBTreePage val[%d]",
-					  page->val[i], i);
+				hg_log_warning("[BUG] Invalid object %p to be marked: HgBTreePage val[%d]",
+					       page->val[i], i);
 			} else {
 				hg_mem_add_flags__inline(obj, flags, TRUE);
 			}
@@ -184,8 +185,8 @@ _hg_btree_page_real_set_flags(gpointer data,
 		if (page->page[page->n_data]) {
 			hg_mem_get_object__inline(page->page[page->n_data], obj);
 			if (obj == NULL) {
-				g_warning("[BUG] Invalid object %p to be marked: HgBTreePage page[%d]",
-					  page->page[page->n_data], page->n_data);
+				hg_log_warning("[BUG] Invalid object %p to be marked: HgBTreePage page[%d]",
+					       page->page[page->n_data], page->n_data);
 			} else {
 				hg_mem_add_flags__inline(obj, flags, TRUE);
 			}
@@ -273,7 +274,7 @@ _hg_btree_real_set_flags(gpointer data,
 	if (tree->root) {
 		hg_mem_get_object__inline(tree->root, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgBTree", tree->root);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgBTree", tree->root);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -413,7 +414,7 @@ hg_btree_page_blance(HgBTreePage  *page,
 		size = page_size + 1;
 	new = hg_btree_page_new(page->parent);
 	if (new == NULL) {
-		g_warning("Failed to allocate a memory.");
+		hg_log_warning("Failed to allocate a memory.");
 		return;
 	}
 	for (i = size + 1; i <= page_size * 2; i++) {
@@ -715,7 +716,7 @@ hg_btree_add(HgBTree *tree,
 	if (!inserted) {
 		page = hg_btree_page_new(tree);
 		if (page == NULL) {
-			g_warning("Failed to allocate a tree page.");
+			hg_log_warning("Failed to allocate a tree page.");
 			return;
 		}
 		page->n_data = 1;
diff --git a/hieroglyph/hgdevice.c b/hieroglyph/hgdevice.c
index 5551111..2d5f233 100644
--- a/hieroglyph/hgdevice.c
+++ b/hieroglyph/hgdevice.c
@@ -28,6 +28,7 @@
 #include <string.h>
 #include <gmodule.h>
 #include "hgdevice.h"
+#include "hglog.h"
 
 /*
  * Private Functions
@@ -45,14 +46,14 @@ _hg_device_open(const gchar *filename)
 		if (open_symbol && close_symbol) {
 			retval = ((HgDeviceOpenFunc)open_symbol) ();
 		} else {
-			g_warning(g_module_error());
+			hg_log_warning(g_module_error());
 			g_module_close(module);
 
 			return NULL;
 		}
 #ifdef DEBUG_MODULES
 	} else {
-		g_warning(g_module_error());
+		hg_log_warning(g_module_error());
 #endif /* DEBUG_MODULES */
 	}
 
@@ -107,7 +108,7 @@ hg_device_new(const gchar *name)
 		g_free(fullmodname);
 	}
 	if (retval == NULL)
-		g_warning("No `%s' device module found.", realname);
+		hg_log_warning("No `%s' device module found.", realname);
 
 	g_free(realname);
 	g_free(modulename);
@@ -164,7 +165,7 @@ hg_device_draw(HgDevice *device,
 				    render->u.debug.func(render->u.debug.data);
 			    break;
 		    default:
-			    g_warning("Unknown rendering code %d\n", render->u.type);
+			    hg_log_warning("Unknown rendering code %d\n", render->u.type);
 			    break;
 		}
 	}
diff --git a/hieroglyph/hgdict.c b/hieroglyph/hgdict.c
index e92b7fa..cefe1ea 100644
--- a/hieroglyph/hgdict.c
+++ b/hieroglyph/hgdict.c
@@ -27,6 +27,7 @@
 
 #include "hgdict.h"
 #include "hgbtree.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hglist.h"
 #include "hgstring.h"
@@ -910,7 +911,7 @@ _hg_dict_traverse_set_flags(gpointer key,
 	HgListIter iter = hg_list_iter_new(list);
 
 	if (iter == NULL) {
-		g_warning("Failed to create an iter to set flags from Dict.");
+		hg_log_warning("Failed to create an iter to set flags from Dict.");
 		return FALSE;
 	}
 	/* no need to mark a key because it's hash value here */
@@ -921,7 +922,7 @@ _hg_dict_traverse_set_flags(gpointer key,
 
 		hg_mem_get_object__inline(node, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: DictNode [list %p]", node, list);
+			hg_log_warning("[BUG] Invalid object %p to be marked: DictNode [list %p]", node, list);
 		} else {
 #ifdef DEBUG_GC
 			G_STMT_START {
@@ -954,7 +955,7 @@ _hg_dict_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(dict->dict, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: Dict tree", dict->dict);
+		hg_log_warning("[BUG] Invalid object %p to be marked: Dict tree", dict->dict);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -988,12 +989,12 @@ _hg_dict_traverse_dup(gpointer key,
 	hg_mem_get_object__inline(key, obj);
 	nnkey = hg_object_dup((HgObject *)nkey);
 	if (nnkey == NULL) {
-		g_warning("[BUG] Failed to duplicate a key during traversing dict.");
+		hg_log_warning("[BUG] Failed to duplicate a key during traversing dict.");
 		nnkey = nkey;
 	}
 	nnval = hg_object_dup((HgObject *)nval);
 	if (nnval == NULL) {
-		g_warning("[BUG] Failed to duplicate a val during traversing dict.");
+		hg_log_warning("[BUG] Failed to duplicate a val during traversing dict.");
 		nnval = nval;
 	}
 	hg_dict_insert(obj->pool, dict, nnkey, nnval);
@@ -1013,7 +1014,7 @@ _hg_dict_real_dup(gpointer data)
 
 	retval = hg_dict_new(obj->pool, dict->n_prealloc);
 	if (retval == NULL) {
-		g_warning("Failed to duplicate a dict.");
+		hg_log_warning("Failed to duplicate a dict.");
 		return NULL;
 	}
 	hg_dict_traverse(dict, _hg_dict_traverse_dup, retval);
@@ -1046,7 +1047,7 @@ _hg_dict_node_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(node->key, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: Dict key", node->key);
+		hg_log_warning("[BUG] Invalid object %p to be marked: Dict key", node->key);
 	} else {
 #ifdef DEBUG_GC
 		G_STMT_START {
@@ -1064,7 +1065,7 @@ _hg_dict_node_real_set_flags(gpointer data,
 	}
 	hg_mem_get_object__inline(node->val, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: Dict val", node->val);
+		hg_log_warning("[BUG] Invalid object %p to be marked: Dict val", node->val);
 	} else {
 #ifdef DEBUG_GC
 		G_STMT_START {
@@ -1105,7 +1106,7 @@ hg_dict_node_new(HgMemPool *pool)
 					 sizeof (HgDictNode),
 					 HG_FL_HGOBJECT | HG_FL_RESTORABLE);
 	if (retval == NULL) {
-		g_warning("Failed to create a dict node.");
+		hg_log_warning("Failed to create a dict node.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -1205,7 +1206,7 @@ hg_dict_new(HgMemPool *pool,
 					 sizeof (HgDict),
 					 HG_FL_HGOBJECT | HG_FL_RESTORABLE | HG_FL_COMPLEX);
 	if (retval == NULL) {
-		g_warning("Failed to create a dict.");
+		hg_log_warning("Failed to create a dict.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -1261,12 +1262,12 @@ hg_dict_insert_forcibly(HgMemPool   *pool,
 
 	if (!force) {
 		if (!hg_mem_pool_is_own_object(obj->pool, key)) {
-			g_warning("key %p isn't allocated from a pool %s\n", key, hg_mem_pool_get_name(obj->pool));
+			hg_log_warning("key %p isn't allocated from a pool %s\n", key, hg_mem_pool_get_name(obj->pool));
 
 			return FALSE;
 		}
 		if (!hg_mem_pool_is_own_object(obj->pool, val)) {
-			g_warning("value %p isn't allocated from a pool %s\n", val, hg_mem_pool_get_name(obj->pool));
+			hg_log_warning("value %p isn't allocated from a pool %s\n", val, hg_mem_pool_get_name(obj->pool));
 
 			return FALSE;
 		}
@@ -1303,7 +1304,7 @@ hg_dict_insert_forcibly(HgMemPool   *pool,
 		dict->n_keys++;
 	}
 	if (dict->n_keys > dict->n_prealloc) {
-		g_warning("FIXME: need to recalculate the prime.");
+		hg_log_warning("FIXME: need to recalculate the prime.");
 	}
 
 	return TRUE;
@@ -1463,7 +1464,7 @@ hg_dict_first(HgDict       *dict,
 	}
 	liter = hg_list_iter_new(iter->val);
 	if (liter == NULL) {
-		g_warning("Failed to create an iter to traverse a Dict.");
+		hg_log_warning("Failed to create an iter to traverse a Dict.");
 		hg_btree_iter_free(iter);
 		return FALSE;
 	}
diff --git a/hieroglyph/hgfile.c b/hieroglyph/hgfile.c
index 458578a..8d890d1 100644
--- a/hieroglyph/hgfile.c
+++ b/hieroglyph/hgfile.c
@@ -32,6 +32,7 @@
 #include <sys/stat.h>
 #include "hgfile.h"
 #include "hgallocator-bfit.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hgstring.h"
 #include "hglineedit.h"
@@ -114,7 +115,7 @@ _hg_file_object_real_set_flags(gpointer data,
 	if (file->filename) {
 		hg_mem_get_object__inline(file->filename, obj);
 		if (obj == NULL) {
-			g_warning("Invalid object %p to be marked: HgFileObject->filename", file->filename);
+			hg_log_warning("Invalid object %p to be marked: HgFileObject->filename", file->filename);
 		} else {
 #ifdef DEBUG_GC
 			G_STMT_START {
@@ -133,7 +134,7 @@ _hg_file_object_real_set_flags(gpointer data,
 	    file->is.buf.buffer) {
 		hg_mem_get_object__inline(file->is.buf.buffer, obj);
 		if (obj == NULL) {
-			g_warning("Invalid object %p to be marked: HgFileObject->buffer", file->is.buf.buffer);
+			hg_log_warning("Invalid object %p to be marked: HgFileObject->buffer", file->is.buf.buffer);
 		} else {
 #ifdef DEBUG_GC
 		G_STMT_START {
@@ -284,7 +285,7 @@ hg_file_object_new(HgMemPool  *pool,
 	retval = hg_mem_alloc_with_flags(pool, sizeof (HgFileObject),
 					 HG_FL_HGOBJECT | HG_FL_COMPLEX);
 	if (retval == NULL) {
-		g_warning("Failed to create a file object.");
+		hg_log_warning("Failed to create a file object.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -306,7 +307,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    len = strlen(p);
 		    retval->filename = hg_mem_alloc(pool, len + 1);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, p, len);
@@ -340,7 +341,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    len = strlen(p);
 		    retval->filename = hg_mem_alloc(pool, len + 1);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, p, len);
@@ -352,7 +353,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    retval->is.buf.buffer = NULL;
 		    retval->is.buf.buffer = hg_mem_alloc(pool, retval->is.buf.bufsize);
 		    if (retval->is.buf.buffer == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    memcpy(retval->is.buf.buffer, p, retval->is.buf.bufsize);
@@ -361,7 +362,7 @@ hg_file_object_new(HgMemPool  *pool,
 	    case HG_FILE_TYPE_STDIN:
 		    retval->filename = hg_mem_alloc(pool, 6);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, "stdin", 5);
@@ -375,7 +376,7 @@ hg_file_object_new(HgMemPool  *pool,
 	    case HG_FILE_TYPE_STDOUT:
 		    retval->filename = hg_mem_alloc(pool, 7);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, "stdout", 6);
@@ -387,7 +388,7 @@ hg_file_object_new(HgMemPool  *pool,
 	    case HG_FILE_TYPE_STDERR:
 		    retval->filename = hg_mem_alloc(pool, 7);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, "stderr", 6);
@@ -399,19 +400,19 @@ hg_file_object_new(HgMemPool  *pool,
 	    case HG_FILE_TYPE_STATEMENT_EDIT:
 		    lineedit = (HgLineEdit *)va_arg(ap, HgLineEdit *);
 		    if (lineedit == NULL) {
-			    g_warning("[BUG] No HgLineEdit instance.");
+			    hg_log_warning("[BUG] No HgLineEdit instance.");
 			    return NULL;
 		    }
 		    retval->filename = hg_mem_alloc(pool, 15);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, "%statementedit", 14);
 		    retval->filename[14] = 0;
 		    p = hg_line_edit_get_statement(lineedit, NULL);
 		    if (p == NULL) {
-			    g_warning("Failed to read a statement.");
+			    hg_log_warning("Failed to read a statement.");
 			    return NULL;
 		    }
 		    retval->access_mode = HG_FILE_MODE_READ;
@@ -419,7 +420,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    retval->is.buf.buffer = NULL;
 		    retval->is.buf.buffer = hg_mem_alloc(pool, retval->is.buf.bufsize);
 		    if (retval->is.buf.buffer == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    memcpy(retval->is.buf.buffer, p, retval->is.buf.bufsize);
@@ -429,19 +430,19 @@ hg_file_object_new(HgMemPool  *pool,
 	    case HG_FILE_TYPE_LINE_EDIT:
 		    lineedit = (HgLineEdit *)va_arg(ap, HgLineEdit *);
 		    if (lineedit == NULL) {
-			    g_warning("[BUG] No HgLineEdit instance.");
+			    hg_log_warning("[BUG] No HgLineEdit instance.");
 			    return NULL;
 		    }
 		    retval->filename = hg_mem_alloc(pool, 10);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, "%lineedit", 9);
 		    retval->filename[9] = 0;
 		    p = hg_line_edit_get_line(lineedit, NULL, TRUE);
 		    if (p == NULL) {
-			    g_warning("Failed to read a statement.");
+			    hg_log_warning("Failed to read a statement.");
 			    return NULL;
 		    }
 		    retval->access_mode = HG_FILE_MODE_READ;
@@ -449,7 +450,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    retval->is.buf.buffer = NULL;
 		    retval->is.buf.buffer = hg_mem_alloc(pool, retval->is.buf.bufsize);
 		    if (retval->is.buf.buffer == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    memcpy(retval->is.buf.buffer, p, retval->is.buf.bufsize);
@@ -462,7 +463,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    len = strlen(p);
 		    retval->filename = hg_mem_alloc(pool, len + 1);
 		    if (retval->filename == NULL) {
-			    g_warning("Failed to allocate a memory for file object.");
+			    hg_log_warning("Failed to allocate a memory for file object.");
 			    return NULL;
 		    }
 		    strncpy(retval->filename, p, len);
@@ -471,7 +472,7 @@ hg_file_object_new(HgMemPool  *pool,
 		    retval->is.callback.user_data = (gpointer)va_arg(ap, gpointer);
 		    break;
 	    default:
-		    g_warning("Unknown file type %d\n", HG_FILE_GET_FILE_TYPE (retval));
+		    hg_log_warning("Unknown file type %d\n", HG_FILE_GET_FILE_TYPE (retval));
 		    retval = NULL;
 		    break;
 	}
@@ -510,7 +511,7 @@ hg_file_object_has_error(HgFileObject *object)
 		    object->error = object->is.callback.vtable->get_error_code(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("[BUG] Invalid file type %d was given to check the error.", HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("[BUG] Invalid file type %d was given to check the error.", HG_FILE_GET_FILE_TYPE (object));
 		    return TRUE;
 	}
 
@@ -556,7 +557,7 @@ hg_file_object_read(HgFileObject *object,
 
 	/* FIXME: need to handle ungetc here properly */
 	if (object->ungetc != 0) {
-		g_warning("FIXME: ungetc handling not yet implemented!!");
+		hg_log_warning("FIXME: ungetc handling not yet implemented!!");
 	}
 	switch (HG_FILE_GET_FILE_TYPE (object)) {
 	    case HG_FILE_TYPE_FILE:
@@ -600,7 +601,7 @@ hg_file_object_read(HgFileObject *object,
 		    object->error = object->is.callback.vtable->get_error_code(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("[BUG] Invalid file type %d was given to be read.", HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("[BUG] Invalid file type %d was given to be read.", HG_FILE_GET_FILE_TYPE (object));
 		    object->error = EACCES;
 		    break;
 	}
@@ -649,7 +650,7 @@ hg_file_object_write(HgFileObject  *object,
 		    object->error = object->is.callback.vtable->get_error_code(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("[BUG] Invalid file type %d to be wrriten.", HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("[BUG] Invalid file type %d to be wrriten.", HG_FILE_GET_FILE_TYPE (object));
 		    object->error = EACCES;
 		    break;
 	}
@@ -699,7 +700,7 @@ hg_file_object_getc(HgFileObject *object)
 			    object->error = object->is.callback.vtable->get_error_code(object->is.callback.user_data);
 			    break;
 		    default:
-			    g_warning("[BUG] Invalid file type %d was given to be get a character.", HG_FILE_GET_FILE_TYPE (object));
+			    hg_log_warning("[BUG] Invalid file type %d was given to be get a character.", HG_FILE_GET_FILE_TYPE (object));
 			    break;
 		}
 	}
@@ -760,7 +761,7 @@ hg_file_object_flush(HgFileObject *object)
 		    retval = object->is.callback.vtable->flush(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("Invalid file type %d was given to be flushed.", HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("Invalid file type %d was given to be flushed.", HG_FILE_GET_FILE_TYPE (object));
 		    break;
 	}
 
@@ -805,7 +806,7 @@ hg_file_object_seek(HgFileObject  *object,
 						object->is.file.mmap.pos = object->is.file.mmap.bufsize;
 					break;
 				default:
-					g_warning("Invalid whence `%d' was given.", whence);
+					hg_log_warning("Invalid whence `%d' was given.", whence);
 					object->error = EINVAL;
 					break;
 			    }
@@ -844,7 +845,7 @@ hg_file_object_seek(HgFileObject  *object,
 					object->is.buf.pos = object->is.buf.bufsize;
 				break;
 			default:
-				g_warning("Invalid whence `%d' was given.", whence);
+				hg_log_warning("Invalid whence `%d' was given.", whence);
 				object->error = EINVAL;
 				break;
 		    }
@@ -853,7 +854,7 @@ hg_file_object_seek(HgFileObject  *object,
 	    case HG_FILE_TYPE_STDIN:
 	    case HG_FILE_TYPE_STDOUT:
 	    case HG_FILE_TYPE_STDERR:
-		    g_warning("Not supported to be sought.");
+		    hg_log_warning("Not supported to be sought.");
 		    object->error = ESPIPE;
 		    break;
 	    case HG_FILE_TYPE_BUFFER_WITH_CALLBACK:
@@ -861,8 +862,8 @@ hg_file_object_seek(HgFileObject  *object,
 		    object->error = object->is.callback.vtable->get_error_code(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("Unknown file type %d was given to be sought.",
-			      HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("Unknown file type %d was given to be sought.",
+				   HG_FILE_GET_FILE_TYPE (object));
 		    break;
 	}
 	object->ungetc = 0;
@@ -903,8 +904,8 @@ hg_file_object_close(HgFileObject *object)
 		    object->is.callback.vtable->close(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("Unknown file type %d was given to be closed.",
-			      HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("Unknown file type %d was given to be closed.",
+				   HG_FILE_GET_FILE_TYPE (object));
 		    break;
 	}
 }
@@ -934,8 +935,8 @@ hg_file_object_is_closed(HgFileObject *object)
 		    retval = object->is.callback.vtable->is_closed(object->is.callback.user_data);
 		    break;
 	    default:
-		    g_warning("Unknown file type %d was given to be closed.",
-			      HG_FILE_GET_FILE_TYPE (object));
+		    hg_log_warning("Unknown file type %d was given to be closed.",
+				   HG_FILE_GET_FILE_TYPE (object));
 		    break;
 	}
 
diff --git a/hieroglyph/hggraphics.c b/hieroglyph/hggraphics.c
index 028e79b..eb131f1 100644
--- a/hieroglyph/hggraphics.c
+++ b/hieroglyph/hggraphics.c
@@ -27,6 +27,7 @@
 
 #include <string.h>
 #include "hggraphics.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hgarray.h"
 #include "hgdict.h"
@@ -80,7 +81,7 @@ _hg_graphic_state_real_set_flags(gpointer data,
 	if (gstate->member) {						\
 		hg_mem_get_object__inline(gstate->member, obj);		\
 		if (obj == NULL) {					\
-			g_warning("Invalid object %p to be marked: Graphics", gstate->member); \
+			hg_log_warning("Invalid object %p to be marked: Graphics", gstate->member); \
 		} else {						\
 			hg_mem_add_flags__inline(obj, flags, TRUE);	\
 		}							\
@@ -127,7 +128,7 @@ _hg_graphic_state_real_copy(gpointer data)
 		return NULL;
 	retval = hg_graphic_state_new(obj->pool);
 	if (retval == NULL) {
-		g_warning("Failed to duplicate a graphic state.");
+		hg_log_warning("Failed to duplicate a graphic state.");
 		return NULL;
 	}
 	memcpy(retval, data, sizeof (HgGraphicState));
@@ -177,7 +178,7 @@ _hg_graphics_real_set_flags(gpointer data,
 	if (member) {							\
 		hg_mem_get_object__inline(member, obj);			\
 		if (obj == NULL) {					\
-			g_warning("Invalid object %p to be marked: Graphics", member); \
+			hg_log_warning("Invalid object %p to be marked: Graphics", member); \
 		} else {						\
 			hg_mem_add_flags__inline(obj, flags, TRUE);	\
 		}							\
@@ -253,7 +254,7 @@ hg_graphic_state_new(HgMemPool *pool)
 
 		return retval;
 	}
-	g_warning("Failed to create a graphic state.");
+	hg_log_warning("Failed to create a graphic state.");
 
 	return NULL;
 }
@@ -285,7 +286,7 @@ hg_graphics_new(HgMemPool *pool)
 
 		return retval;
 	}
-	g_warning("Failed to create a graphic state.");
+	hg_log_warning("Failed to create a graphic state.");
 
 	return NULL;
 }
@@ -359,7 +360,7 @@ hg_graphics_set_graphic_size(HgGraphics *graphics,
 	g_return_val_if_fail (graphics->current_gstate != NULL, FALSE);
 
 	if (graphics->current_page->node) {
-		g_warning("Can't change the page size after the rendering code is invoked.");
+		hg_log_warning("Can't change the page size after the rendering code is invoked.");
 		return FALSE;
 	}
 
diff --git a/hieroglyph/hglineedit.c b/hieroglyph/hglineedit.c
index 28861c8..8ba8339 100644
--- a/hieroglyph/hglineedit.c
+++ b/hieroglyph/hglineedit.c
@@ -30,6 +30,7 @@
 #include <errno.h>
 #include "hglineedit.h"
 #include "hgfile.h"
+#include "hglog.h"
 #include "hgmem.h"
 
 
@@ -81,13 +82,13 @@ _hg_line_edit_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(lineedit->stdin, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgLineEdit", lineedit->stdin);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgLineEdit", lineedit->stdin);
 	} else {
 		hg_mem_add_flags__inline(obj, flags, TRUE);
 	}
 	hg_mem_get_object__inline(lineedit->stdout, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgLineEdit", lineedit->stdout);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgLineEdit", lineedit->stdout);
 	} else {
 		hg_mem_add_flags__inline(obj, flags, TRUE);
 	}
diff --git a/hieroglyph/hglist.c b/hieroglyph/hglist.c
index c4a48d4..01e24ff 100644
--- a/hieroglyph/hglist.c
+++ b/hieroglyph/hglist.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "hglist.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hgallocator-bfit.h"
 
@@ -122,8 +123,8 @@ _hg_list_real_set_flags(gpointer data,
 	if (list->data && HG_LIST_IS_OBJECT_NODE (list)) {
 		hg_mem_get_object__inline(list->data, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgList data",
-				  list->data);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgList data",
+				       list->data);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -132,7 +133,7 @@ _hg_list_real_set_flags(gpointer data,
 	if ((tmp = hg_list_next(list)) != NULL) {
 		hg_mem_get_object__inline(tmp, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgList next node", tmp);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgList next node", tmp);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -141,7 +142,7 @@ _hg_list_real_set_flags(gpointer data,
 	if ((tmp = hg_list_previous(list)) != NULL) {
 		hg_mem_get_object__inline(tmp, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgList previous node", tmp);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgList previous node", tmp);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -184,21 +185,21 @@ _hg_list_iter_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(iter->top, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgListIter top node", iter->top);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgListIter top node", iter->top);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
 	}
 	hg_mem_get_object__inline(iter->last, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgListIter last node", iter->last);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgListIter last node", iter->last);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
 	}
 	hg_mem_get_object__inline(iter->current, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgListIter current node", iter->current);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgListIter current node", iter->current);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -239,7 +240,7 @@ _hg_list_get_last_node(HgList *list)
 			if (hg_list_next(tmp) != NULL ||
 			    hg_list_previous(tmp) != NULL) {
 				/* found incomplete node */
-				g_warning("[BUG] incomplete HgList node %p found.", tmp);
+				hg_log_warning("[BUG] incomplete HgList node %p found.", tmp);
 			} else {
 				/* this can be used as the last node */
 				return tmp;
@@ -253,8 +254,8 @@ _hg_list_get_last_node(HgList *list)
 		/* validate node */
 		if (tmp == list) {
 			/* detected the circular reference */
-			g_warning("[BUG] Circular reference happened without the last node mark: %p",
-				  list);
+			hg_log_warning("[BUG] Circular reference happened without the last node mark: %p",
+				       list);
 			/* workaround */
 			return hg_list_previous(list);
 		}
@@ -292,8 +293,8 @@ _hg_list_real_append(HgList   *list,
 		if (!HG_LIST_IS_UNUSED (last)) {
 			hg_mem_get_object__inline(last, obj);
 			if (obj == NULL) {
-				g_warning("[BUG] Invalid object %p is given to append a list.",
-					  last);
+				hg_log_warning("[BUG] Invalid object %p is given to append a list.",
+					       last);
 				return NULL;
 			}
 			tmp = hg_list_new(obj->pool);
@@ -332,8 +333,8 @@ _hg_list_real_prepend(HgList   *list,
 		if (!HG_LIST_IS_UNUSED (top)) {
 			hg_mem_get_object__inline(top, obj);
 			if (obj == NULL) {
-				g_warning("[BUG] Invalid object %p is given to prepend a list.",
-					  top);
+				hg_log_warning("[BUG] Invalid object %p is given to prepend a list.",
+					       top);
 				return NULL;
 			}
 			tmp = hg_list_new(obj->pool);
@@ -458,7 +459,7 @@ hg_list_length(HgList *list)
 
 	/* validate node */
 	if (l == NULL) {
-		g_warning("[BUG] no loop detected in HgList %p", list);
+		hg_log_warning("[BUG] no loop detected in HgList %p", list);
 	}
 
 	return retval;
@@ -504,8 +505,8 @@ hg_list_remove(HgList   *list,
 
 	/* validate node */
 	if (l == NULL) {
-		g_warning("[BUG] no loop detected in HgList %p during removing %p",
-			  list, data);
+		hg_log_warning("[BUG] no loop detected in HgList %p during removing %p",
+			       list, data);
 		top = list;
 	} else {
 		if (!top)
diff --git a/hieroglyph/hglog.c b/hieroglyph/hglog.c
new file mode 100644
index 0000000..329aeba
--- /dev/null
+++ b/hieroglyph/hglog.c
@@ -0,0 +1,206 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/* 
+ * hglog.c
+ * Copyright (C) 2006 Akira TAGOH
+ * 
+ * Authors:
+ *   Akira TAGOH  <at@gclab.org>
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "hglog.h"
+#include "hgdict.h"
+#include "hgfile.h"
+#include "hgmem.h"
+#include "hgstring.h"
+#include "hgvaluenode.h"
+#include "vm.h"
+
+
+static void _hg_log_default_handler(HgLogType    log_type,
+				    const gchar *subtype,
+				    const gchar *message);
+
+static gboolean __hg_log_initialized = FALSE;
+static HgDict *__hg_log_options_dict = NULL;
+static HgVM *__hg_log_vm = NULL;
+static gchar const *log_type_to_string[] = {
+	"Info",
+	"Debug",
+	"Warning",
+	"Error",
+};
+static HgLogFunc __hg_log_handler = _hg_log_default_handler;
+
+/*
+ * Private Functions
+ */
+static void
+_hg_log_default_handler(HgLogType    log_type,
+			const gchar *subtype,
+			const gchar *message)
+{
+	HgFileObject *file;
+
+	if (__hg_log_vm) {
+		file = hg_vm_get_io(__hg_log_vm, VM_IO_STDERR);
+	} else {
+		if (!hg_file_is_initialized())
+			hg_file_init();
+		file = __hg_file_stderr;
+	}
+	hg_file_object_printf(file, "%s ***%s%s%s %s\n",
+			      log_type_to_string[log_type],
+			      (subtype ? " " : ""),
+			      (subtype ? subtype : ""),
+			      (subtype ? ":" : ""),
+			      message);
+}
+
+/*
+ * Public Functions
+ */
+/* initializer */
+gboolean
+hg_log_init(HgVM   *vm,
+	    HgDict *dict)
+{
+	HgMemObject *obj;
+
+	g_return_val_if_fail (vm != NULL, FALSE);
+	g_return_val_if_fail (dict != NULL, FALSE);
+
+	if (__hg_log_options_dict == NULL) {
+		hg_mem_get_object__inline(dict, obj);
+		if (obj == NULL) {
+			hg_log_warning("Invalid object %p to be set as Log Dict.", dict);
+			return FALSE;
+		}
+		hg_mem_set_lock(obj);
+		__hg_log_options_dict = dict;
+
+		hg_mem_get_object__inline(vm, obj);
+		if (obj == NULL) {
+			hg_log_warning("Invalid object %p to be set as Log VM.", vm);
+			return FALSE;
+		}
+		hg_mem_set_lock(obj);
+		__hg_log_vm = vm;
+		__hg_log_handler = _hg_log_default_handler;
+
+		__hg_log_initialized = TRUE;
+	}
+
+	return TRUE;
+}
+
+void
+hg_log_finalize(void)
+{
+	HgMemObject *obj;
+
+	if (__hg_log_initialized) {
+		hg_mem_get_object__inline(__hg_log_options_dict, obj);
+		if (obj != NULL) {
+			hg_mem_set_unlock(obj);
+		}
+		__hg_log_options_dict = NULL;
+		hg_mem_get_object__inline(__hg_log_vm, obj);
+		if (obj != NULL) {
+			hg_mem_set_unlock(obj);
+		}
+		__hg_log_vm = NULL;
+		__hg_log_initialized = FALSE;
+	}
+}
+
+/* utilities */
+void
+hg_log_set_default_handler(HgLogFunc func)
+{
+	g_return_if_fail (func);
+
+	__hg_log_handler = func;
+}
+
+void
+hg_log(HgLogType    log_type,
+       const gchar *subtype,
+       const gchar *format,
+       ...)
+{
+	va_list ap;
+
+	va_start(ap, format);
+	hg_logv(log_type, subtype, format, ap);
+	va_end(ap);
+}
+
+void
+hg_logv(HgLogType    log_type,
+	const gchar *subtype,
+	const gchar *format,
+	va_list      va_args)
+{
+	HgValueNode *node;
+	HgString *string = NULL;
+
+	g_return_if_fail (format != NULL);
+
+	if (subtype == NULL) {
+		gchar *buffer = g_strdup_vprintf(format, va_args);
+
+		/* just invoke a default handler */
+		__hg_log_handler(log_type, subtype, buffer);
+		g_free(buffer);
+		return;
+	}
+
+	g_return_if_fail (__hg_log_initialized);
+
+	if ((node = hg_dict_lookup_with_string(__hg_log_options_dict, subtype)) != NULL) {
+		HgMemPool *pool = hg_vm_get_current_pool(__hg_log_vm);
+
+		string = hg_string_new(pool, -1);
+		hg_string_append_vprintf(string, format, va_args);
+
+		if (HG_IS_VALUE_BOOLEAN (node)) {
+			if (HG_VALUE_GET_BOOLEAN (node)) {
+				/* just invoke a default handler */
+				__hg_log_handler(log_type, subtype, hg_string_get_string(string));
+			}
+		} else if (HG_IS_VALUE_OPERATOR (node) ||
+			   (HG_IS_VALUE_ARRAY (node) && hg_object_is_executable((HgObject *)node))) {
+			HgValueNode *strnode = NULL, *subnode, *lognode;
+			HG_VALUE_MAKE_STRING (strnode, string);
+			lognode = hg_vm_get_name_node(__hg_log_vm, log_type_to_string[log_type]);
+			subnode = hg_vm_get_name_node(__hg_log_vm, subtype);
+			hg_log_warning("FIXME: not yet supported.");
+
+			if (strnode)
+				hg_mem_free(strnode);
+		} else {
+			hg_log_warning("Invalid object specified for logger.");
+		}
+
+		if (string)
+			hg_mem_free(string);
+	}
+}
diff --git a/hieroglyph/hglog.h b/hieroglyph/hglog.h
new file mode 100644
index 0000000..c2aa462
--- /dev/null
+++ b/hieroglyph/hglog.h
@@ -0,0 +1,66 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/* 
+ * hglog.h
+ * Copyright (C) 2006 Akira TAGOH
+ * 
+ * Authors:
+ *   Akira TAGOH  <at@gclab.org>
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+#ifndef __HG_LOG_H__
+#define __HG_LOG_H__
+
+#include <hieroglyph/hgtypes.h>
+
+G_BEGIN_DECLS
+
+
+typedef void (*HgLogFunc)(HgLogType     log_type,
+			  const gchar  *subtype,
+			  const gchar  *message);
+
+#define hg_log_info(...)				\
+	hg_log(HG_LOG_TYPE_INFO, NULL, __VA_ARGS__)
+#ifdef DEBUG
+#define hg_log_debug(_type_, ...)				\
+	hg_log(HG_LOG_TYPE_DEBUG, (_type_), __VA_ARGS__)
+#else
+#define hg_log_debug(_type_, ...)
+#endif /* DEBUG */
+#define hg_log_warning(...)				\
+	hg_log(HG_LOG_TYPE_WARNING, NULL, __VA_ARGS__)
+#define hg_log_error(...)				\
+	hg_log(HG_LOG_TYPE_ERROR, NULL, __VA_ARGS__)
+
+
+gboolean hg_log_init               (HgVM        *vm,
+				    HgDict      *dict);
+void     hg_log_finalize           (void);
+void     hg_log_set_default_handler(HgLogFunc    func);
+void     hg_log                    (HgLogType    log_type,
+				    const gchar *subtype,
+				    const gchar *format,
+				    ...);
+void     hg_logv                   (HgLogType    log_type,
+				    const gchar *subtype,
+				    const gchar *format,
+				    va_list      va_args);
+
+
+G_END_DECLS
+
+#endif /* __HG_LOG_H__ */
diff --git a/hieroglyph/hgmem.c b/hieroglyph/hgmem.c
index b6514bd..c4c4637 100644
--- a/hieroglyph/hgmem.c
+++ b/hieroglyph/hgmem.c
@@ -30,6 +30,7 @@
 #include <unistd.h>
 #include "hgmem.h"
 #include "hgallocator-private.h"
+#include "hglog.h"
 
 #define VTABLE_TREE_N_NODE	3
 
@@ -183,7 +184,7 @@ hg_mem_init(void)
 		if (!_hg_object_vtable_tree) {
 			_hg_object_vtable_tree = g_hash_table_new(NULL, g_direct_equal);
 			if (_hg_object_vtable_tree == NULL) {
-				g_warning("Failed to initialize VTable tree.");
+				hg_log_warning("Failed to initialize VTable tree.");
 				return;
 			}
 			_hg_object_vtable_array = g_ptr_array_new();
@@ -523,7 +524,7 @@ hg_mem_free(gpointer data)
 
 	hg_mem_get_object__inline(data, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p is given to be freed.", data);
+		hg_log_warning("[BUG] Invalid object %p is given to be freed.", data);
 		return FALSE;
 	} else {
 		const HgObjectVTable const *vtable;
@@ -555,7 +556,7 @@ hg_mem_resize(gpointer data,
 
 	hg_mem_get_object__inline(data, obj);
 	if (obj == NULL) {
-		g_warning("Invalid object %p was about to be resized.", data);
+		hg_log_warning("Invalid object %p was about to be resized.", data);
 		return NULL;
 	}
 
@@ -571,7 +572,7 @@ hg_mem_get_object_size(gpointer data)
 
 	hg_mem_get_object__inline(data, obj);
 	if (obj == NULL) {
-		g_warning("Invalid object %p was about to get an object size.", data);
+		hg_log_warning("Invalid object %p was about to get an object size.", data);
 		return 0;
 	}
 
@@ -763,8 +764,8 @@ hg_object_get_vtable(HgObject *object)
 		return NULL;
 	}
 	if (id > _hg_object_vtable_array->len) {
-		g_warning("[BUG] Invalid vtable ID found: %p id: %d latest id: %u\n",
-			  object, id, _hg_object_vtable_array->len);
+		hg_log_warning("[BUG] Invalid vtable ID found: %p id: %d latest id: %u\n",
+			       object, id, _hg_object_vtable_array->len);
 
 		return NULL;
 	}
@@ -791,7 +792,7 @@ hg_object_set_vtable(HgObject                   *object,
 		g_hash_table_insert(_hg_object_vtable_tree, (gpointer)vtable, GUINT_TO_POINTER (id));
 	}
 	if (id > 255) {
-		g_warning("[BUG] Invalid vtable ID found in tree: %p id %u\n", object, id);
+		hg_log_warning("[BUG] Invalid vtable ID found in tree: %p id %u\n", object, id);
 		id = 0;
 	}
 	HG_OBJECT_SET_VTABLE_ID (object, id);
diff --git a/hieroglyph/hgpage.c b/hieroglyph/hgpage.c
index 74fd0ac..45d2ef7 100644
--- a/hieroglyph/hgpage.c
+++ b/hieroglyph/hgpage.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "hgpage.h"
+#include "hglog.h"
 
 
 /*
@@ -60,7 +61,7 @@ hg_page_new_with_pagesize(HgPageSize size)
 	gdouble width, height;
 
 	if (!hg_page_get_size(size, &width, &height)) {
-		g_warning("Failed to get a paper size.");
+		hg_log_warning("Failed to get a paper size.");
 		return NULL;
 	}
 	return hg_page_new_with_size(width, height);
@@ -74,7 +75,7 @@ hg_page_new_with_size(gdouble width,
 
 	retval = _hg_page_new();
 	if (retval == NULL) {
-		g_warning("Failed to create a page object.");
+		hg_log_warning("Failed to create a page object.");
 		return NULL;
 	}
 	retval->width = width;
@@ -217,7 +218,7 @@ hg_page_get_size(HgPageSize  size,
 		    *height = 148;
 		    break;
 	    default:
-		    g_warning("Unknown page size type %d", size);
+		    hg_log_warning("Unknown page size type %d", size);
 		    *width = 0;
 		    *height = 0;
 		    return FALSE;
diff --git a/hieroglyph/hgpath.c b/hieroglyph/hgpath.c
index 9a5c98c..fd4e7fd 100644
--- a/hieroglyph/hgpath.c
+++ b/hieroglyph/hgpath.c
@@ -28,6 +28,7 @@
 #include <math.h>
 #include <string.h>
 #include "hgpath.h"
+#include "hglog.h"
 #include "hgmem.h"
 
 
@@ -74,7 +75,7 @@ _hg_path_node_real_set_flags(gpointer data,
 	if (node->next) {
 		hg_mem_get_object__inline(node->next, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgPathNode", node->next);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgPathNode", node->next);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -126,7 +127,7 @@ _hg_path_real_set_flags(gpointer data,
 	if (path->node) {
 		hg_mem_get_object__inline(path->node, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: HgPathNode (in HgPath)", path->node);
+			hg_log_warning("[BUG] Invalid object %p to be marked: HgPathNode (in HgPath)", path->node);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -333,18 +334,18 @@ hg_path_compute_current_point(HgPath  *path,
 		switch (node->type) {
 		    case HG_PATH_CURVETO:
 			    if (!currentpoint) {
-				    g_warning("[BUG] no current point found in %d.", node->type);
+				    hg_log_warning("[BUG] no current point found in %d.", node->type);
 				    return FALSE;
 			    }
 			    if (node->next == NULL ||
 				node->next->next == NULL) {
-				    g_warning("[BUG] Invalid path found in %d.", node->type);
+				    hg_log_warning("[BUG] Invalid path found in %d.", node->type);
 				    return FALSE;
 			    }
 			    node = node->next->next;
 		    case HG_PATH_LINETO:
 			    if (!currentpoint) {
-				    g_warning("[BUG] no current point found in %d.", node->type);
+				    hg_log_warning("[BUG] no current point found in %d.", node->type);
 				    return FALSE;
 			    }
 		    case HG_PATH_MOVETO:
@@ -355,14 +356,14 @@ hg_path_compute_current_point(HgPath  *path,
 		    case HG_PATH_RCURVETO:
 			    if (node->next == NULL ||
 				node->next->next == NULL) {
-				    g_warning("[BUG] Invalid path found in %d.", node->type);
+				    hg_log_warning("[BUG] Invalid path found in %d.", node->type);
 				    return FALSE;
 			    }
 			    node = node->next->next;
 		    case HG_PATH_RMOVETO:
 		    case HG_PATH_RLINETO:
 			    if (!currentpoint) {
-				    g_warning("[BUG] no current point found in %d.", node->type);
+				    hg_log_warning("[BUG] no current point found in %d.", node->type);
 				    return FALSE;
 			    }
 			    *x = *x + node->x;
@@ -371,7 +372,7 @@ hg_path_compute_current_point(HgPath  *path,
 		    case HG_PATH_ARC:
 			    if (node->next == NULL ||
 				node->next->next == NULL) {
-				    g_warning("[BUG] Invalid path found in %d.\n", node->type);
+				    hg_log_warning("[BUG] Invalid path found in %d.\n", node->type);
 				    return FALSE;
 			    }
 			    G_STMT_START {
@@ -391,7 +392,7 @@ hg_path_compute_current_point(HgPath  *path,
 		    case HG_PATH_MATRIX:
 			    break;
 		    default:
-			    g_warning("[BUG] Unknown path %d was given.", node->type);
+			    hg_log_warning("[BUG] Unknown path %d was given.", node->type);
 			    return FALSE;
 		}
 	}
@@ -495,7 +496,7 @@ hg_path_get_bbox(HgPath     *path,
 		    case HG_PATH_ARC:
 			    flag = TRUE;
 			    if (node->next == NULL || node->next->next == NULL) {
-				    g_warning("[BUG] Invalid path for arc.");
+				    hg_log_warning("[BUG] Invalid path for arc.");
 				    break;
 			    }
 			    G_STMT_START {
@@ -543,7 +544,7 @@ hg_path_get_bbox(HgPath     *path,
 			    /* this isn't used to calculate bbox at all */
 			    break;
 		    default:
-			    g_warning("[BUG] Unknown path type %d to examine current bbox.", node->type);
+			    hg_log_warning("[BUG] Unknown path type %d to examine current bbox.", node->type);
 			    return FALSE;
 		}
 	}
diff --git a/hieroglyph/hgplugins.c b/hieroglyph/hgplugins.c
index 692f4cd..8047535 100644
--- a/hieroglyph/hgplugins.c
+++ b/hieroglyph/hgplugins.c
@@ -28,6 +28,7 @@
 #include <string.h>
 #include "hgplugins.h"
 #include "hgmem.h"
+#include "hglog.h"
 
 
 static void _hg_plugin_real_free     (gpointer data);
@@ -88,7 +89,7 @@ _hg_plugin_load(HgMemPool   *pool,
 #define _CHECK_SYMBOL(_sym)						\
 		g_module_symbol(module, #_sym, &(_sym));		\
 		if ((_sym) == NULL) {					\
-			g_warning(g_module_error());			\
+			hg_log_warning(g_module_error());			\
 			g_module_close(module);				\
 			return NULL;					\
 		}
@@ -100,11 +101,11 @@ _hg_plugin_load(HgMemPool   *pool,
 		/* initialize a plugin and get a HgPlugin instance */
 		retval = ((HgPluginNewFunc)plugin_new) (pool);
 		if (retval == NULL) {
-			g_warning("Failed to create an instance of the plugin `%s'", filename);
+			hg_log_warning("Failed to create an instance of the plugin `%s'", filename);
 			g_module_close(module);
 		} else if (retval->version < HG_PLUGIN_VERSION ||
 			   retval->vtable == NULL) {
-			g_warning("`%s' is an invalid plugin.", filename);
+			hg_log_warning("`%s' is an invalid plugin.", filename);
 			g_module_close(module);
 			retval = NULL;
 		} else {
@@ -112,7 +113,7 @@ _hg_plugin_load(HgMemPool   *pool,
 		}
 #ifdef DEBUG_PLUGIN
 	} else {
-		g_warning(g_module_error());
+		hg_log_warning(g_module_error());
 #endif
 	}
 
@@ -134,7 +135,7 @@ hg_plugin_new(HgMemPool    *pool,
 					 sizeof (HgPlugin),
 					 HG_FL_HGOBJECT | HG_FL_COMPLEX);
 	if (retval == NULL) {
-		g_warning("Failed to create a plugin.");
+		hg_log_warning("Failed to create a plugin.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -175,7 +176,7 @@ hg_plugin_open(HgMemPool    *pool,
 		    modulename = g_strdup_printf("libdevice-%s.so", realname);
 		    break;
 	    default:
-		    g_warning("Unknown plugin type: %d", type);
+		    hg_log_warning("Unknown plugin type: %d", type);
 		    return NULL;
 	}
 	if ((modpath = g_getenv("HIEROGLYPH_PLUGIN_PATH")) != NULL) {
@@ -213,12 +214,12 @@ hg_plugin_open(HgMemPool    *pool,
 		g_free(fullmodname);
 	}
 	if (retval == NULL) {
-		g_warning("No `%s' %s plugin module found.", realname, typenames[type]);
+		hg_log_warning("No `%s' %s plugin module found.", realname, typenames[type]);
 	} else {
 		/* initialize a plugin */
 		if (retval->vtable->init == NULL ||
 		    !retval->vtable->init()) {
-			g_warning("Failed to initialize a plugin `%s'", realname);
+			hg_log_warning("Failed to initialize a plugin `%s'", realname);
 			retval = NULL;
 		}
 	}
@@ -243,8 +244,8 @@ hg_plugin_load(HgPlugin *plugin,
 	if (retval) {
 		plugin->is_loaded = TRUE;
 	} else {
-		g_warning("Failed to load a plugin `%s'",
-			  g_module_name(plugin->module));
+		hg_log_warning("Failed to load a plugin `%s'",
+			       g_module_name(plugin->module));
 	}
 
 	return retval;
diff --git a/hieroglyph/hgrender.c b/hieroglyph/hgrender.c
index 51d4c77..4148b65 100644
--- a/hieroglyph/hgrender.c
+++ b/hieroglyph/hgrender.c
@@ -27,6 +27,7 @@
 
 #include <string.h>
 #include "hgrender.h"
+#include "hglog.h"
 #include "hgmem.h"
 
 
@@ -81,7 +82,7 @@ _hg_render_fill_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(render->u.fill.path, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgRenderFill.", render->u.fill.path);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgRenderFill.", render->u.fill.path);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -109,14 +110,14 @@ _hg_render_stroke_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(render->u.stroke.path, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgRenderStroke->path.", render->u.stroke.path);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgRenderStroke->path.", render->u.stroke.path);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
 	}
 	hg_mem_get_object__inline(render->u.stroke.dashline_pattern, obj);
 	if (obj == NULL) {
-		g_warning("[BUG] Invalid object %p to be marked: HgRenderStroke->dashline_pattern.", render->u.stroke.dashline_pattern);
+		hg_log_warning("[BUG] Invalid object %p to be marked: HgRenderStroke->dashline_pattern.", render->u.stroke.dashline_pattern);
 	} else {
 		if (!hg_mem_is_flags__inline(obj, flags))
 			hg_mem_add_flags__inline(obj, flags, TRUE);
diff --git a/hieroglyph/hgstack.c b/hieroglyph/hgstack.c
index 294a705..489e2d7 100644
--- a/hieroglyph/hgstack.c
+++ b/hieroglyph/hgstack.c
@@ -27,6 +27,7 @@
 
 #include <stdlib.h>
 #include "hgstack.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hgfile.h"
 #include "hgstring.h"
@@ -82,7 +83,7 @@ _hg_stack_real_set_flags(gpointer data,
 	for (list = stack->stack; list != NULL; list = g_list_next(list)) {
 		hg_mem_get_object__inline(list->data, obj);
 		if (obj == NULL) {
-			g_warning("Invalid object %p to be marked: HgValueNode in stack.", list->data);
+			hg_log_warning("Invalid object %p to be marked: HgValueNode in stack.", list->data);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_set_flags__inline(obj, flags, TRUE);
@@ -117,7 +118,7 @@ _hg_stack_real_dup(gpointer data)
 
 	retval = hg_stack_new(obj->pool, stack->max_depth);
 	if (retval == NULL) {
-		g_warning("Failed to duplicate a stack.");
+		hg_log_warning("Failed to duplicate a stack.");
 		return NULL;
 	}
 	retval->stack = g_list_copy(stack->stack);
@@ -141,7 +142,7 @@ hg_stack_new(HgMemPool *pool,
 	retval = hg_mem_alloc_with_flags(pool, sizeof (HgStack),
 					 HG_FL_HGOBJECT);
 	if (retval == NULL) {
-		g_warning("Failed to create a stack.");
+		hg_log_warning("Failed to create a stack.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
diff --git a/hieroglyph/hgstring.c b/hieroglyph/hgstring.c
index 54a9fa8..c51aa3d 100644
--- a/hieroglyph/hgstring.c
+++ b/hieroglyph/hgstring.c
@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include <string.h>
 #include "hgstring.h"
+#include "hglog.h"
 #include "hgmem.h"
 
 #define HG_STRING_ALLOC_SIZE	256
@@ -76,7 +77,7 @@ _hg_string_real_set_flags(gpointer data,
 		flags &= ~HG_FL_RESTORABLE;
 		hg_mem_get_object__inline(string->strings, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: String", string->strings);
+			hg_log_warning("[BUG] Invalid object %p to be marked: String", string->strings);
 		} else {
 #ifdef DEBUG_GC
 			G_STMT_START {
@@ -173,7 +174,7 @@ hg_string_new(HgMemPool *pool,
 					 sizeof (HgString),
 					 HG_FL_HGOBJECT | HG_FL_COMPLEX);
 	if (retval == NULL) {
-		g_warning("Failed to create a string.");
+		hg_log_warning("Failed to create a string.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -195,7 +196,7 @@ hg_string_new(HgMemPool *pool,
 	retval->current = retval->strings;
 	if (retval->strings == NULL) {
 		hg_mem_free(retval);
-		g_warning("Failed to create a string.");
+		hg_log_warning("Failed to create a string.");
 		return NULL;
 	}
 
@@ -251,7 +252,7 @@ hg_string_append_c(HgString *string,
 		gpointer p = hg_mem_resize(string->strings, string->allocated_size + HG_STRING_ALLOC_SIZE + 1);
 
 		if (p == NULL) {
-			g_warning("Failed to resize a string.");
+			hg_log_warning("Failed to resize a string.");
 			return FALSE;
 		}
 		string->current = string->strings = p;
@@ -286,7 +287,7 @@ hg_string_append(HgString    *string,
 		gpointer p = hg_mem_resize(string->strings, n_unit * HG_STRING_ALLOC_SIZE);
 
 		if (p == NULL) {
-			g_warning("Failed to resize a string.");
+			hg_log_warning("Failed to resize a string.");
 			return FALSE;
 		}
 		string->current = string->strings = p;
@@ -374,7 +375,7 @@ hg_string_fix_string_size(HgString *string)
 
 		p = hg_mem_resize(string->strings, string->length + 1);
 		if (p == NULL) {
-			g_warning("Failed to resize a string.");
+			hg_log_warning("Failed to resize a string.");
 			return FALSE;
 		}
 		string->strings = p;
diff --git a/hieroglyph/hgtypes.h b/hieroglyph/hgtypes.h
index 88d554d..f9da6a9 100644
--- a/hieroglyph/hgtypes.h
+++ b/hieroglyph/hgtypes.h
@@ -45,6 +45,7 @@ typedef struct _HieroGlyphLineEditVTable	HgLineEditVTable;
 /* hglist.h */
 typedef struct _HieroGlyphList			HgList;
 typedef struct _HieroGlyphListIter		*HgListIter;
+/* hglog.h */
 /* hgmem.h */
 typedef struct _HieroGlyphAllocatorVTable	HgAllocatorVTable;
 typedef struct _HieroGlyphAllocator		HgAllocator;
@@ -99,14 +100,14 @@ typedef struct _HieroGlyphDevice		HgDevice;
 
 typedef gboolean            (*HgCompareFunc)       (gconstpointer a,
 						    gconstpointer b);
-typedef gboolean            (*HgTraverseFunc)      (gpointer    key,
-						    gpointer    val,
-						    gpointer    data);
-typedef void                (*HgDebugFunc)         (gpointer    data);
+typedef gboolean            (*HgTraverseFunc)      (gpointer      key,
+						    gpointer      val,
+						    gpointer      data);
+typedef void                (*HgDebugFunc)         (gpointer      data);
 typedef HgAllocatorVTable * (*HgAllocatorTypeFunc) (void);
-typedef HgPlugin          * (*HgPluginNewFunc)     (HgMemPool  *pool);
-typedef gboolean            (*HgOperatorFunc)      (HgOperator *op,
-						    gpointer    vm);
+typedef HgPlugin          * (*HgPluginNewFunc)     (HgMemPool    *pool);
+typedef gboolean            (*HgOperatorFunc)      (HgOperator   *op,
+						    gpointer      vm);
 
 typedef enum {
 	HG_MEM_GLOBAL    = 1 << 0,  /* without this, that means the local pool */
@@ -213,6 +214,14 @@ typedef enum {
 	HG_FILE_POS_END     = SEEK_END
 } HgFilePosType;
 
+/* hglog.h */
+typedef enum {
+	HG_LOG_TYPE_INFO    = 0,
+	HG_LOG_TYPE_DEBUG   = 1,
+	HG_LOG_TYPE_WARNING = 2,
+	HG_LOG_TYPE_ERROR   = 3,
+} HgLogType;
+
 typedef enum {
 	HG_PAGE_4A0 = 1,
 	HG_PAGE_2A0 = 2,
diff --git a/hieroglyph/hgvaluenode.c b/hieroglyph/hgvaluenode.c
index 3466b81..d06ca72 100644
--- a/hieroglyph/hgvaluenode.c
+++ b/hieroglyph/hgvaluenode.c
@@ -33,6 +33,7 @@
 #include "hgbtree.h"
 #include "hgdict.h"
 #include "hgfile.h"
+#include "hglog.h"
 #include "hgmem.h"
 #include "hgstring.h"
 
@@ -70,7 +71,7 @@ _hg_value_node_register_type(const HgValueNodeTypeInfo *info)
 	g_return_val_if_fail (__hg_value_node_is_initialized, FALSE);
 
 	if (hg_btree_find(__hg_value_node_type_tree, GUINT_TO_POINTER (info->type_id))) {
-		g_warning("type_id %d already registered.", info->type_id);
+		hg_log_warning("type_id %d already registered.", info->type_id);
 		return FALSE;
 	}
 	hg_btree_add(__hg_value_node_type_tree,
@@ -104,9 +105,9 @@ _hg_value_node_real_set_flags(gpointer data,
 		    if (((HgValueNodePointer *)node)->value) {
 			    hg_mem_get_object__inline(((HgValueNodePointer *)node)->value, obj);
 			    if (obj == NULL) {
-				    g_warning("[BUG] Invalid object %p with node type %d",
-					      ((HgValueNodePointer *)node)->value,
-					      HG_VALUE_GET_VALUE_TYPE (node));
+				    hg_log_warning("[BUG] Invalid object %p with node type %d",
+						   ((HgValueNodePointer *)node)->value,
+						   HG_VALUE_GET_VALUE_TYPE (node));
 			    }
 		    }
 		    break;
@@ -114,7 +115,7 @@ _hg_value_node_real_set_flags(gpointer data,
 	    case HG_TYPE_VALUE_MARK:
 		    break;
 	    default:
-		    g_warning("Unknown node type %d to set flags", HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("Unknown node type %d to set flags", HG_VALUE_GET_VALUE_TYPE (node));
 		    break;
 	}
 
@@ -164,7 +165,7 @@ _hg_value_node_real_relocate(gpointer           data,
 	    case HG_TYPE_VALUE_MARK:
 		    break;
 	    default:
-		    g_warning("Unknown node type %d to be relocated", HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("Unknown node type %d to be relocated", HG_VALUE_GET_VALUE_TYPE (node));
 		    break;
 	}
 }
@@ -185,7 +186,7 @@ _hg_value_node_real_dup(gpointer data)
 	}
 	retval = hg_value_node_new(obj->pool, HG_VALUE_GET_VALUE_TYPE (node));
 	if (retval == NULL) {
-		g_warning("Failed to duplicate a node.");
+		hg_log_warning("Failed to duplicate a node.");
 		return NULL;
 	}
 	HG_OBJECT_SET_STATE (&retval->object, HG_OBJECT_GET_STATE (&node->object));
@@ -224,7 +225,7 @@ _hg_value_node_real_dup(gpointer data)
 		    HG_VALUE_SET_PLUGIN (retval, HG_VALUE_GET_PLUGIN (node));
 		    break;
 	    default:
-		    g_warning("Unknown node type %d to be duplicated", HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("Unknown node type %d to be duplicated", HG_VALUE_GET_VALUE_TYPE (node));
 		    hg_mem_free(retval);
 		    return NULL;
 	}
@@ -257,7 +258,7 @@ _hg_value_node_real_copy(gpointer data)
 	}
 	retval = hg_value_node_new(obj->pool, HG_VALUE_GET_VALUE_TYPE (node));
 	if (retval == NULL) {
-		g_warning("Failed to duplicate a node.");
+		hg_log_warning("Failed to duplicate a node.");
 		return NULL;
 	}
 	HG_OBJECT_SET_STATE (&retval->object, HG_OBJECT_GET_STATE (&node->object));
@@ -296,7 +297,7 @@ _hg_value_node_real_copy(gpointer data)
 		    _copy_object (retval, PLUGIN, HG_VALUE_GET_PLUGIN (node));
 		    break;
 	    default:
-		    g_warning("Unknown node type %d to be duplicated", HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("Unknown node type %d to be duplicated", HG_VALUE_GET_VALUE_TYPE (node));
 		    hg_mem_free(retval);
 		    return NULL;
 	}
@@ -413,8 +414,8 @@ _hg_value_node_real_to_string(gpointer data)
 		    hg_string_append(retval, "-mark-", -1);
 		    break;
 	    default:
-		    g_warning("Unknown node type %d to be converted to string.",
-			      HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("Unknown node type %d to be converted to string.",
+				   HG_VALUE_GET_VALUE_TYPE (node));
 		    break;
 	}
 	if (str)
@@ -508,8 +509,8 @@ hg_value_node_get_type_name(guint type_id)
 
 	if ((info = hg_btree_find(__hg_value_node_type_tree,
 				  GUINT_TO_POINTER (type_id))) == NULL) {
-		g_warning("Unknown type ID %d. Failed to get a type name.",
-			  type_id);
+		hg_log_warning("Unknown type ID %d. Failed to get a type name.",
+			       type_id);
 		return NULL;
 	}
 
@@ -528,13 +529,13 @@ hg_value_node_new(HgMemPool   *pool,
 
 	if ((info = hg_btree_find(__hg_value_node_type_tree,
 				  GUINT_TO_POINTER (type_id))) == NULL) {
-		g_warning("Unknown type ID %d. Failed to create a HgValueNode.", type_id);
+		hg_log_warning("Unknown type ID %d. Failed to create a HgValueNode.", type_id);
 		return NULL;
 	}
 	retval = hg_mem_alloc_with_flags(pool, info->struct_size,
 					 HG_FL_HGOBJECT | HG_FL_RESTORABLE);
 	if (retval == NULL) {
-		g_warning("Failed to create a node.");
+		hg_log_warning("Failed to create a node.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -608,8 +609,8 @@ hg_value_node_get_hash(const HgValueNode *node)
 		    retval = _get_hash(node, PLUGIN);
 		    break;
 	    default:
-		    g_warning("[BUG] Unknown node type %d to generate hash",
-			      HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("[BUG] Unknown node type %d to generate hash",
+				   HG_VALUE_GET_VALUE_TYPE (node));
 		    break;
 	}
 
@@ -671,8 +672,8 @@ hg_value_node_compare(const HgValueNode *a,
 		    retval = TRUE;
 		    break;
 	    default:
-		    g_warning("[BUG] Unknown node type is given to compare: %d",
-			      HG_VALUE_GET_VALUE_TYPE (a));
+		    hg_log_warning("[BUG] Unknown node type is given to compare: %d",
+				   HG_VALUE_GET_VALUE_TYPE (a));
 		    break;
 	}
 
@@ -739,8 +740,8 @@ hg_value_node_compare_content(const HgValueNode *a,
 		    retval = TRUE;
 		    break;
 	    default:
-		    g_warning("[BUG] Unknown node type is given to compare: %d",
-			      HG_VALUE_GET_VALUE_TYPE (a));
+		    hg_log_warning("[BUG] Unknown node type is given to compare: %d",
+				   HG_VALUE_GET_VALUE_TYPE (a));
 		    break;
 	}
 
diff --git a/hieroglyph/iarray.c b/hieroglyph/iarray.c
index 2391746..1fdd8e0 100644
--- a/hieroglyph/iarray.c
+++ b/hieroglyph/iarray.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "iarray.h"
+#include "hglog.h"
 #include "hgmem.h"
 
 #define HG_INT_ARRAY_ALLOC_SIZE		256
@@ -67,7 +68,7 @@ _hg_int_array_real_set_flags(gpointer data,
 	if (iarray->arrays) {
 		hg_mem_get_object__inline(iarray->arrays, obj);
 		if (obj == NULL) {
-			g_warning("[BUG] Invalid object %p to be marked: IntArray", iarray->arrays);
+			hg_log_warning("[BUG] Invalid object %p to be marked: IntArray", iarray->arrays);
 		} else {
 			if (!hg_mem_is_flags__inline(obj, flags))
 				hg_mem_add_flags__inline(obj, flags, TRUE);
@@ -146,7 +147,7 @@ hg_int_array_append(HgIntArray *iarray,
 					   sizeof (gint32) * (iarray->allocated_arrays + HG_INT_ARRAY_ALLOC_SIZE));
 
 		if (p == NULL) {
-			g_warning("Failed to resize an int array.");
+			hg_log_warning("Failed to resize an int array.");
 			return FALSE;
 		} else {
 			iarray->arrays = p;
diff --git a/hieroglyph/ibtree.c b/hieroglyph/ibtree.c
index 991868d..9ac41f4 100644
--- a/hieroglyph/ibtree.c
+++ b/hieroglyph/ibtree.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "ibtree.h"
+#include "hglog.h"
 
 
 static HgBTreePage *hg_btree_page_new                 (HgBTree      *tree);
@@ -196,7 +197,7 @@ hg_btree_page_blance(HgBTree      *tree,
 		size = tree->page_size + 1;
 	new = hg_btree_page_new(tree);
 	if (new == NULL) {
-		g_warning("Failed to allocate a memory.");
+		hg_log_warning("Failed to allocate a memory.");
 		return;
 	}
 	for (i = size + 1; i <= tree->page_size * 2; i++) {
diff --git a/hieroglyph/ilist.c b/hieroglyph/ilist.c
index 1a0e215..95fd76e 100644
--- a/hieroglyph/ilist.c
+++ b/hieroglyph/ilist.c
@@ -26,6 +26,7 @@
 #endif
 
 #include "ilist.h"
+#include "hglog.h"
 
 /*
  * Most code are duplicate from HgList.
@@ -95,7 +96,7 @@ _hg_list_get_last_node(HgList *list)
 			if (hg_list_next(tmp) != NULL ||
 			    hg_list_previous(tmp) != NULL) {
 				/* found incomplete node */
-				g_warning("[BUG] incomplete HgList node %p found.", tmp);
+				hg_log_warning("[BUG] incomplete HgList node %p found.", tmp);
 			} else {
 				/* this can be used as the last node */
 				return tmp;
@@ -109,8 +110,8 @@ _hg_list_get_last_node(HgList *list)
 		/* validate node */
 		if (tmp == list) {
 			/* detected the circular reference */
-			g_warning("[BUG] Circular reference happened without the last node mark: %p",
-				  list);
+			hg_log_warning("[BUG] Circular reference happened without the last node mark: %p",
+				       list);
 			/* workaround */
 			return hg_list_previous(list);
 		}
@@ -273,7 +274,7 @@ _hg_list_length(HgList *list)
 
 	/* validate node */
 	if (l == NULL) {
-		g_warning("[BUG] no loop detected in HgList %p", list);
+		hg_log_warning("[BUG] no loop detected in HgList %p", list);
 	}
 
 	return retval;
@@ -319,8 +320,8 @@ _hg_list_remove(HgList   *list,
 
 	/* validate node */
 	if (l == NULL) {
-		g_warning("[BUG] no loop detected in HgList %p during removing %p",
-			  list, data);
+		hg_log_warning("[BUG] no loop detected in HgList %p during removing %p",
+			       list, data);
 		top = list;
 	} else {
 		if (!top)
diff --git a/hieroglyph/operator.c b/hieroglyph/operator.c
index 4219ec0..7db1742 100644
--- a/hieroglyph/operator.c
+++ b/hieroglyph/operator.c
@@ -39,6 +39,7 @@
 #include "hgdict.h"
 #include "hgfile.h"
 #include "hglineedit.h"
+#include "hglog.h"
 #include "hgmatrix.h"
 #include "hgpath.h"
 #include "hgstack.h"
@@ -1244,7 +1245,7 @@ G_STMT_START
 		    i = depth - 3;
 		    break;
 	    default:
-		    g_warning("Unknown emulation level %d\n", type);
+		    hg_log_warning("Unknown emulation level %d\n", type);
 		    break;
 	}
 	if (i < 0) {
@@ -3074,7 +3075,7 @@ G_STMT_START
 				break;
 			}
 		} else {
-			g_warning("unknown open type: %d", file_type);
+			hg_log_warning("unknown open type: %d", file_type);
 		}
 		if (file == NULL) {
 			_hg_operator_set_error(vm, op, VM_e_VMerror);
@@ -6491,8 +6492,8 @@ G_STMT_START
 			    break;
 		    case HG_TYPE_VALUE_END:
 		    default:
-			    g_warning("[BUG] Unknown node type %d was given.",
-				      HG_VALUE_GET_VALUE_TYPE (node));
+			    hg_log_warning("[BUG] Unknown node type %d was given.",
+					   HG_VALUE_GET_VALUE_TYPE (node));
 			    _hg_operator_set_error(vm, op, VM_e_typecheck);
 
 			    return retval;
@@ -6612,7 +6613,7 @@ G_STMT_START
 		for (i = 0; i < ddepth; i++) {
 			ndict = hg_stack_index(dstack, i);
 			if (!HG_IS_VALUE_DICT (ndict)) {
-				g_warning("[BUG] Invalid dictionary was in the dictionary stack.");
+				hg_log_warning("[BUG] Invalid dictionary was in the dictionary stack.");
 				return retval;
 			}
 			dict = HG_VALUE_GET_DICT (ndict);
@@ -7517,7 +7518,7 @@ _hg_operator_real_set_flags(gpointer data,
 
 	hg_mem_get_object__inline(op->name, obj);
 	if (obj == NULL) {
-		g_warning("Invalid object %p to be marked: HgOperator->name", op->name);
+		hg_log_warning("Invalid object %p to be marked: HgOperator->name", op->name);
 	} else {
 #ifdef DEBUG_GC
 		G_STMT_START {
@@ -7987,7 +7988,7 @@ hg_operator_new(HgMemPool      *pool,
 	retval = hg_mem_alloc_with_flags(pool, sizeof (HgOperator),
 					 HG_FL_HGOBJECT);
 	if (retval == NULL) {
-		g_warning("Failed to create an operator.");
+		hg_log_warning("Failed to create an operator.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -7997,7 +7998,7 @@ hg_operator_new(HgMemPool      *pool,
 	len = strlen(name);
 	retval->name = hg_mem_alloc(pool, len + 1);
 	if (retval->name == NULL) {
-		g_warning("Failed to create an operator.");
+		hg_log_warning("Failed to create an operator.");
 		return NULL;
 	}
 	strncpy(retval->name, name, len);
@@ -8022,7 +8023,7 @@ hg_operator_init(HgVM *vm)
 	type = hg_vm_get_emulation_level(vm);
 	if (type < VM_EMULATION_LEVEL_1 ||
 	    type > VM_EMULATION_LEVEL_3) {
-		g_warning("[BUG] Unknown emulation level %d", type);
+		hg_log_warning("[BUG] Unknown emulation level %d", type);
 
 		return FALSE;
 	}
diff --git a/hieroglyph/scanner.c b/hieroglyph/scanner.c
index 76b7d2e..1d55594 100644
--- a/hieroglyph/scanner.c
+++ b/hieroglyph/scanner.c
@@ -31,6 +31,7 @@
 #include "hgarray.h"
 #include "hgdict.h"
 #include "hgfile.h"
+#include "hglog.h"
 #include "hgstring.h"
 #include "hgvaluenode.h"
 #include "iarray.h"
@@ -312,9 +313,9 @@ _hg_scanner_get_object(HgVM         *vm,
 						need_loop = FALSE;
 					} else if (c == '~') {
 						/* ASCII85 encoding */
-						g_warning("FIXME: implement me");
+						hg_log_warning("FIXME: implement me");
 					} else {
-						g_warning("FIXME: implement me");
+						hg_log_warning("FIXME: implement me");
 						hg_file_object_ungetc(file, c);
 					}
 					break;
@@ -325,9 +326,9 @@ _hg_scanner_get_object(HgVM         *vm,
 						need_loop = FALSE;
 					} else if (c == '~') {
 						/* ASCII85 encoding */
-						g_warning("FIXME: implement me");
+						hg_log_warning("FIXME: implement me");
 					} else {
-						g_warning("FIXME: implement me");
+						hg_log_warning("FIXME: implement me");
 						hg_file_object_ungetc(file, c);
 					}
 					break;
@@ -394,7 +395,7 @@ _hg_scanner_get_object(HgVM         *vm,
 					was_comment = TRUE;
 					break;
 				default:
-					g_warning("[BUG] unknown control object %c.", c);
+					hg_log_warning("[BUG] unknown control object %c.", c);
 					break;
 			    }
 			    break;
@@ -483,7 +484,7 @@ _hg_scanner_get_object(HgVM         *vm,
 					}
 					break;
 				default:
-					g_warning("[BUG] it may be unlikely to appear HG_SCAN_C_NAME in token type %d\n", token_type);
+					hg_log_warning("[BUG] it may be unlikely to appear HG_SCAN_C_NAME in token type %d\n", token_type);
 					break;
 			    }
 			    break;
@@ -533,7 +534,7 @@ _hg_scanner_get_object(HgVM         *vm,
 		    case HG_SCAN_C_BINARY:
 			    break;
 		    default:
-			    g_warning("Unknown character %c(%d)[%d]", c, c, __hg_scanner_token[c]);
+			    hg_log_warning("Unknown character %c(%d)[%d]", c, c, __hg_scanner_token[c]);
 			    break;
 		}
 	}
@@ -586,7 +587,7 @@ _hg_scanner_get_object(HgVM         *vm,
 	    default:
 		    /* XXX */
 		    if (!was_comment)
-			    g_warning("FIXME: unknown token type %d\n", token_type);
+			    hg_log_warning("FIXME: unknown token type %d\n", token_type);
 		    break;
 	}
 
@@ -736,7 +737,7 @@ _hg_scanner_parse_number(HgVM          *vm,
 						is_valid = FALSE;
 						break;
 					default:
-						g_warning("[BUG] it may be unlikely to appear HG_SCAN_C_NAME in token type %d\n", token_type);
+						hg_log_warning("[BUG] it may be unlikely to appear HG_SCAN_C_NAME in token type %d\n", token_type);
 						is_valid = FALSE;
 						break;
 				    }
@@ -794,7 +795,7 @@ _hg_scanner_parse_number(HgVM          *vm,
 					}
 					break;
 				default:
-					g_warning("[BUG] it may be unlikely to appear HG_SCAN_C_NUMERAL in token type %d\n", token_type);
+					hg_log_warning("[BUG] it may be unlikely to appear HG_SCAN_C_NUMERAL in token type %d\n", token_type);
 					goto non_numeral_handler;
 			    }
 			    break;
@@ -822,7 +823,7 @@ _hg_scanner_parse_number(HgVM          *vm,
 				intdigits = (guint)log10(di) + 1;
 			if (has_radix) {
 				/* this is unlikely */
-				g_warning("[BUG] numeric with radix is going to be the real.");
+				hg_log_warning("[BUG] numeric with radix is going to be the real.");
 				return FALSE;
 			}
 			if (floatarray) {
diff --git a/hieroglyph/version.h.in b/hieroglyph/version.h.in
index d185a96..c649c61 100644
--- a/hieroglyph/version.h.in
+++ b/hieroglyph/version.h.in
@@ -29,7 +29,7 @@
 G_BEGIN_DECLS
 
 #define HIEROGLYPH_VERSION	"@VERSION@"
-#define HIEROGLYPH_UUID		"de8df9d1-2e02-45db-9c8c-906a0e87d5bb"
+#define HIEROGLYPH_UUID		"118f9f31-4fa8-45fa-9343-f9c124b0ab6c"
 
 const char *__hg_rcsid G_GNUC_UNUSED = "$Rev$";
 
diff --git a/hieroglyph/vm.c b/hieroglyph/vm.c
index f7328c0..516e593 100644
--- a/hieroglyph/vm.c
+++ b/hieroglyph/vm.c
@@ -37,6 +37,7 @@
 #include "hgfile.h"
 #include "hglineedit.h"
 #include "hglist.h"
+#include "hglog.h"
 #include "hgplugins.h"
 #include "hgstack.h"
 #include "hgstring.h"
@@ -432,7 +433,7 @@ hg_vm_new(HgVMEmulationType type)
 	retval = hg_mem_alloc_with_flags(__hg_vm_mem_pool, sizeof (HgVM),
 					 HG_FL_HGOBJECT);
 	if (retval == NULL) {
-		g_warning("Failed to create a virtual machine.");
+		hg_log_warning("Failed to create a virtual machine.");
 		return NULL;
 	}
 	HG_OBJECT_INIT_STATE (&retval->object);
@@ -461,7 +462,7 @@ hg_vm_new(HgVMEmulationType type)
 					     (allow_resize ? HG_MEM_RESIZABLE : 0));
 	g_free(name);
 	if (retval->local_pool == NULL) {
-		g_warning("Failed to create a local memory pool");
+		hg_log_warning("Failed to create a local memory pool");
 		return NULL;
 	}
 #ifdef ENABLE_GLOBAL_POOL
@@ -473,7 +474,7 @@ hg_vm_new(HgVMEmulationType type)
 	hg_mem_pool_use_global_mode(retval->global_pool, TRUE);
 	g_free(name);
 	if (retval->global_pool == NULL) {
-		g_warning("Failed to create a global memory pool");
+		hg_log_warning("Failed to create a global memory pool");
 		return NULL;
 	}
 #else
@@ -486,14 +487,14 @@ hg_vm_new(HgVMEmulationType type)
 					       (allow_resize ? HG_MEM_RESIZABLE : 0));
 	g_free(name);
 	if (retval->graphic_pool == NULL) {
-		g_warning("Failed to create a graphic memory pool");
+		hg_log_warning("Failed to create a graphic memory pool");
 		return NULL;
 	}
 
 	/* internal use */
 	retval->name_dict = hg_dict_new(retval->global_pool, 1024);
 	if (retval->name_dict == NULL) {
-		g_warning("Failed to create a name dict.");
+		hg_log_warning("Failed to create a name dict.");
 		return NULL;
 	}
 	hg_mem_add_root_node(retval->global_pool, retval->name_dict);
@@ -513,7 +514,7 @@ hg_vm_new(HgVMEmulationType type)
 	if (retval->ostack == NULL ||
 	    retval->estack == NULL ||
 	    retval->dstack == NULL) {
-		g_warning("Failed to create stacks.");
+		hg_log_warning("Failed to create stacks.");
 		return NULL;
 	}
 	hg_mem_add_root_node(retval->local_pool, retval->ostack);
@@ -531,7 +532,7 @@ hg_vm_new(HgVMEmulationType type)
 	    retval->statusdict == NULL ||
 	    retval->serverdict == NULL ||
 	    retval->font == NULL) {
-		g_warning("Failed to create local dictionaries.");
+		hg_log_warning("Failed to create local dictionaries.");
 		return NULL;
 	}
 	hg_mem_add_root_node(retval->local_pool, retval->errordict);
@@ -545,7 +546,7 @@ hg_vm_new(HgVMEmulationType type)
 	retval->globalfont = hg_dict_new(retval->global_pool, 128);
 	if (retval->systemdict == NULL ||
 	    retval->globalfont == NULL) {
-		g_warning("Failed to create global dictionaries.");
+		hg_log_warning("Failed to create global dictionaries.");
 		return NULL;
 	}
 	hg_mem_add_root_node(retval->global_pool, retval->systemdict);
@@ -720,7 +721,7 @@ hg_vm_is_global_object(HgVM        *vm,
 		    retval = (vm->local_pool != obj->pool);
 		    break;
 	    default:
-		    g_warning("Failed to consider if the object is a global object due to the unknown type ID: %d", HG_VALUE_GET_VALUE_TYPE (node));
+		    hg_log_warning("Failed to consider if the object is a global object due to the unknown type ID: %d", HG_VALUE_GET_VALUE_TYPE (node));
 		    break;
 	}
 
@@ -779,7 +780,7 @@ hg_vm_get_io(HgVM       *vm,
 	    case VM_IO_STDERR:
 		    return vm->stderr;
 	    default:
-		    g_warning("Unknown I/O type %d", type);
+		    hg_log_warning("Unknown I/O type %d", type);
 		    break;
 	}
 
@@ -807,7 +808,7 @@ hg_vm_set_io(HgVM         *vm,
 		    vm->stderr = file;
 		    break;
 	    default:
-		    g_warning("Unknown I/O type %d", type);
+		    hg_log_warning("Unknown I/O type %d", type);
 		    break;
 	}
 }
@@ -841,7 +842,7 @@ hg_vm_load_plugin(HgVM        *vm,
 	g_return_val_if_fail (filename != NULL, FALSE);
 
 	if (hg_dict_lookup_with_string(vm->plugin_table, filename) != NULL) {
-		g_warning("`%s' plugin is already loaded.", filename);
+		hg_log_warning("`%s' plugin is already loaded.", filename);
 		return FALSE;
 	}
 	plugin = hg_plugin_open(vm->local_pool, filename, HG_PLUGIN_EXTENSION);
@@ -878,7 +879,7 @@ hg_vm_unload_plugin(HgVM        *vm,
 	g_return_val_if_fail (filename != NULL, FALSE);
 
 	if ((val = hg_dict_lookup_with_string(vm->plugin_table, filename)) == NULL) {
-		g_warning("`%s' plugin isn't yet loaded.", filename);
+		hg_log_warning("`%s' plugin isn't yet loaded.", filename);
 		return FALSE;
 	}
 
@@ -1138,9 +1139,9 @@ hg_vm_set_error(HgVM        *vm,
 		}
 		hs2 = hg_object_to_string((HgObject *)errnode);
 		if (enode == NULL) {
-			g_warning("Multiple errors occurred.\n  prevoius error: unknown or this happened before set /errorname in %s\n  current error: %s in %s\n", name, HG_VALUE_GET_NAME (__hg_vm_errorname[error]), hg_string_get_string(hs2));
+			hg_log_warning("Multiple errors occurred.\n  prevoius error: unknown or this happened before set /errorname in %s\n  current error: %s in %s\n", name, HG_VALUE_GET_NAME (__hg_vm_errorname[error]), hg_string_get_string(hs2));
 		} else {
-			g_warning("Multiple errors occurred.\n  previous error: %s in %s\n  current error: %s in %s\n", HG_VALUE_GET_NAME (enode), name, HG_VALUE_GET_NAME (__hg_vm_errorname[error]), hg_string_get_string(hs2));
+			hg_log_warning("Multiple errors occurred.\n  previous error: %s in %s\n  current error: %s in %s\n", HG_VALUE_GET_NAME (enode), name, HG_VALUE_GET_NAME (__hg_vm_errorname[error]), hg_string_get_string(hs2));
 		}
 		if (p)
 			g_free(p);
@@ -1154,7 +1155,7 @@ hg_vm_set_error(HgVM        *vm,
 	_hg_stack_use_stack_validator(vm->dstack, FALSE);
 	proc = hg_dict_lookup(vm->errordict, __hg_vm_errorname[error]);
 	if (proc == NULL) {
-		g_warning("[BUG] no error handler for /%s\n", HG_VALUE_GET_NAME (__hg_vm_errorname[error]));
+		hg_log_warning("[BUG] no error handler for /%s\n", HG_VALUE_GET_NAME (__hg_vm_errorname[error]));
 		hg_file_object_printf(vm->stderr, "\nOperand stack:\n");
 		hg_stack_dump(vm->ostack, vm->stderr);
 		hg_file_object_printf(vm->stderr, "\nExecution stack:\n");
@@ -1222,8 +1223,8 @@ hg_vm_set_error_from_file(HgVM         *vm,
 		    break;
 	    default:
 		    strerror_r(hg_file_object_get_error(file), buffer, 4096);
-		    g_warning("%s: need to support errno %d\n  %s\n",
-			      __FUNCTION__, hg_file_object_get_error(file), buffer);
+		    hg_log_warning("%s: need to support errno %d\n  %s\n",
+				   __FUNCTION__, hg_file_object_get_error(file), buffer);
 		    break;
 	}
 	hg_file_object_clear_error(file);
@@ -1274,8 +1275,8 @@ hg_vm_main(HgVM *vm)
 		    case HG_TYPE_VALUE_DICT:
 		    case HG_TYPE_VALUE_NULL:
 		    case HG_TYPE_VALUE_MARK:
-			    g_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
-				      __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
+			    hg_log_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
+					   __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
 			    hg_stack_pop(vm->estack);
 			    retval = hg_stack_push(vm->ostack, node);
 			    if (!retval) {
@@ -1308,8 +1309,8 @@ hg_vm_main(HgVM *vm)
 						    _hg_vm_set_error(vm, file, VM_e_stackoverflow, FALSE);
 				    }
 			    } else {
-				    g_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
-					      __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
+				    hg_log_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
+						   __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
 				    hg_stack_pop(vm->estack);
 				    retval = hg_stack_push(vm->ostack, node);
 				    if (!retval) {
@@ -1333,8 +1334,8 @@ hg_vm_main(HgVM *vm)
 				    hg_object_set_state((HgObject *)node, state);
 				    retval = hg_stack_push(vm->estack, node);
 			    } else {
-				    g_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
-					      __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
+				    hg_log_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
+						   __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
 				    hg_stack_pop(vm->estack);
 				    retval = hg_stack_push(vm->ostack, node);
 			    }
@@ -1366,8 +1367,8 @@ hg_vm_main(HgVM *vm)
 					    }
 				    }
 			    } else {
-				    g_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
-					      __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
+				    hg_log_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
+						   __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
 				    hg_stack_pop(vm->estack);
 				    retval = hg_stack_push(vm->ostack, node);
 				    if (!retval) {
@@ -1412,8 +1413,8 @@ hg_vm_main(HgVM *vm)
 					    }
 				    }
 			    } else {
-				    g_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
-					      __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
+				    hg_log_warning("[BUG] %s: an object (node type %d) which isn't actually executable, was pushed into the estack.",
+						   __FUNCTION__, HG_VALUE_GET_VALUE_TYPE (node));
 				    hg_stack_pop(vm->estack);
 				    retval = hg_stack_push(vm->ostack, node);
 				    if (!retval) {
@@ -1422,13 +1423,13 @@ hg_vm_main(HgVM *vm)
 			    }
 			    break;
 		    default:
-			    g_warning("[BUG] Unknown node type %d was given into the estack.",
-				      HG_VALUE_GET_VALUE_TYPE (node));
+			    hg_log_warning("[BUG] Unknown node type %d was given into the estack.",
+					   HG_VALUE_GET_VALUE_TYPE (node));
 			    hg_stack_pop(vm->estack);
 			    break;
 		}
 		if (!retval && !hg_vm_has_error(vm)) {
-			g_warning("[BUG] probably unknown error happened.");
+			hg_log_warning("[BUG] probably unknown error happened.");
 			break;
 		}
 	}
diff --git a/plugins/debug/debug-main.c b/plugins/debug/debug-main.c
index 7572295..c7ce966 100644
--- a/plugins/debug/debug-main.c
+++ b/plugins/debug/debug-main.c
@@ -26,6 +26,7 @@
 #endif
 
 #include <hieroglyph/hgdict.h>
+#include <hieroglyph/hglog.h>
 #include <hieroglyph/hgmem.h>
 #include <hieroglyph/hgplugins.h>
 #include <hieroglyph/hgstack.h>
@@ -157,7 +158,7 @@ plugin_load(HgPlugin *plugin,
 	g_return_val_if_fail (vm != NULL, FALSE);
 
 	if (plugin->user_data != NULL) {
-		g_warning("already loaded.");
+		hg_log_warning("already loaded.");
 		return FALSE;
 	}
 	systemdict = hg_vm_get_dict_systemdict(vm);
@@ -187,7 +188,7 @@ plugin_unload(HgPlugin *plugin,
 	g_return_val_if_fail (vm != NULL, FALSE);
 
 	if (plugin->user_data != NULL) {
-		g_warning("not yet loaded.");
+		hg_log_warning("not yet loaded.");
 		return FALSE;
 	}
 
diff --git a/plugins/libedit/libedit-main.c b/plugins/libedit/libedit-main.c
index 2dae288..8a26cac 100644
--- a/plugins/libedit/libedit-main.c
+++ b/plugins/libedit/libedit-main.c
@@ -33,6 +33,7 @@
 #include <hieroglyph/hgdict.h>
 #include <hieroglyph/hgfile.h>
 #include <hieroglyph/hglineedit.h>
+#include <hieroglyph/hglog.h>
 #include <hieroglyph/hgmem.h>
 #include <hieroglyph/hgplugins.h>
 #include <hieroglyph/hgstack.h>
@@ -286,7 +287,7 @@ plugin_load(HgPlugin *plugin,
 	g_return_val_if_fail (vm != NULL, FALSE);
 
 	if (plugin->user_data != NULL) {
-		g_warning("already loaded.");
+		hg_log_warning("already loaded.");
 		return FALSE;
 	}
 	plugin->user_data = hg_vm_get_line_editor(vm);
@@ -328,7 +329,7 @@ plugin_unload(HgPlugin *plugin,
 	g_return_val_if_fail (vm != NULL, FALSE);
 
 	if (plugin->user_data != NULL) {
-		g_warning("not yet loaded.");
+		hg_log_warning("not yet loaded.");
 		return FALSE;
 	}
 	hg_vm_set_line_editor(vm, plugin->user_data);
diff --git a/plugins/test/test-main.c b/plugins/test/test-main.c
index 679766c..7284b74 100644
--- a/plugins/test/test-main.c
+++ b/plugins/test/test-main.c
@@ -28,6 +28,7 @@
 #include <hieroglyph/hgarray.h>
 #include <hieroglyph/hgdict.h>
 #include <hieroglyph/hgfile.h>
+#include <hieroglyph/hglog.h>
 #include <hieroglyph/hgmem.h>
 #include <hieroglyph/hgplugins.h>
 #include <hieroglyph/hgstack.h>
@@ -244,7 +245,7 @@ plugin_load(HgPlugin *plugin,
 	g_return_val_if_fail (vm != NULL, FALSE);
 
 	if (plugin->user_data != NULL) {
-		g_warning("already loaded.");
+		hg_log_warning("already loaded.");
 		return FALSE;
 	}
 	systemdict = hg_vm_get_dict_systemdict(vm);
@@ -277,7 +278,7 @@ plugin_unload(HgPlugin *plugin,
 	g_return_val_if_fail (vm != NULL, FALSE);
 
 	if (plugin->user_data != NULL) {
-		g_warning("not yet loaded.");
+		hg_log_warning("not yet loaded.");
 		return FALSE;
 	}