TSettingsKeyImpl::SetValueByID: compiler warning about pointer aliasinglibsynthesis_3.0.2.28_at_pr_day+syncevolution-0.9

engineinterface.cpp: In member function 'sysync::TSyError sysync::TSettingsKeyImpl::SetValueByID(sysync::sInt32, sysync::sInt32, sysync::uInt16, const void*, sysync::memSize)':
engineinterface.cpp:495: error: dereferencing pointer 'bP.140' does break strict-aliasing rules
engineinterface.cpp:498: error: dereferencing pointer 'bP.141' does break strict-aliasing rules

g++ 4.4 is unhappy about this code. Reading from the variable and writing into it via
another pointer certainly looks a bit strange, although I guess it must work reliably
(can't write before read). Better avoid the pointer casting and use a union...

1 files changed, 11 insertions, 5 deletions

diff --git a/src/sysync/engineinterface.cpp b/src/sysync/engineinterface.cpp
index e6a85fd..7fefed9 100644
--- a/src/sysync/engineinterface.cpp
+++ b/src/sysync/engineinterface.cpp
@@ -486,20 +486,26 @@ TSyError TSettingsKeyImpl::SetValueByID(
       tempInt = *((sInt64 *)aBuffer);
     intConv:
       // convert integer into native type
-      bP = &tempInt; // re-use as temp buffer
+      union {
+        sInt64 buffer64;
+        sInt32 buffer32;
+        sInt16 buffer16;
+        sInt8  buffer8;
+      } buffer;
+      bP = &buffer;
       switch (valType) {
         case VALTYPE_INT8:
-          siz=1; *((sInt8 *)bP) = tempInt;
+          siz=1; buffer.buffer8 = tempInt;
           break;
         case VALTYPE_INT16:
-          siz=2; *((sInt16 *)bP) = tempInt;
+          siz=2; buffer.buffer16 = tempInt;
           break;
         case VALTYPE_INT32:
-          siz=4; *((sInt32 *)bP) = tempInt;
+          siz=4; buffer.buffer32 = tempInt;
           break;
         case VALTYPE_INT64:
         case VALTYPE_TIME64: // native timestamp
-          siz=8; *((sInt64 *)bP) = tempInt;
+          siz=8; buffer.buffer64 = tempInt;
           break;
         default:
           // other types (like text) cannot set as integer