Add -help option and usage message when unknown options are given

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

2 files changed, 29 insertions, 1 deletions

diff --git a/man/xconsole.man b/man/xconsole.man
index 07476c0..606d6bb 100644
--- a/man/xconsole.man
+++ b/man/xconsole.man
@@ -73,6 +73,9 @@ lines of message history instead of growing the text buffer without bound
 .I count
 of zero \- the default \- is treated as placing no limit on the history).
 .TP 8
+.B \-help
+This option indicates that \fIxconsole\fP should print a usage message and exit.
+.TP 8
 .B \-version
 This option indicates that \fIxconsole\fP should print its version and exit.
 .SH X DEFAULTS
diff --git a/xconsole.c b/xconsole.c
index 20cbacd..a4b3136 100644
--- a/xconsole.c
+++ b/xconsole.c
@@ -608,6 +608,20 @@ InsertSelection(Widget w, XtPointer client_data, Atom *selection, Atom *type,
     OpenConsole ();
 }
 
+static void _X_NORETURN
+usage(int exitval)
+{
+    const char *usage_message =
+    "usage: xconsole [-toolkitoption  ...] [-file file-name] [-notify|-nonotify]\n"
+    "                [-stripNonprint] [-daemon] [-verbose] [-exitOnFail]\n"
+    "                [-saveLines count]\n"
+    "       xconsole -help\n"
+    "       xconsole -version\n";
+
+    fputs(usage_message, stderr);
+    exit(exitval);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -619,10 +633,13 @@ main(int argc, char *argv[])
     /* Handle args that don't require opening a display */
     for (int n = 1; n < argc; n++) {
 	const char *argn = argv[n];
-	/* accept single or double dash for -version */
+	/* accept single or double dash for -help & -version */
 	if (argn[0] == '-' && argn[1] == '-') {
 	    argn++;
 	}
+	if (strcmp(argn, "-help") == 0) {
+	    usage(0);
+	}
 	if (strcmp(argn, "-version") == 0) {
 	    puts(PACKAGE_STRING);
 	    exit(0);
@@ -631,6 +648,14 @@ main(int argc, char *argv[])
 
     top = XtInitialize ("xconsole", "XConsole", options, XtNumber (options),
 			&argc, argv);
+    if (argc != 1) {
+        fputs("Unknown argument(s):", stderr);
+        for (int n = 1; n < argc; n++) {
+            fprintf(stderr, " %s", argv[n]);
+        }
+        fputs("\n\n", stderr);
+        usage(1);
+    }
 
     XtGetApplicationResources (top, (XtPointer)&app_resources, resources,
 			       XtNumber (resources), NULL, 0);