On 30.08.2012 00:13, Graeme Geldenhuys wrote: > Signal received. Signal: SIGSEGV, Segmentation fault. > > #0 0040E1BB :0 SYSTEM_WAITFREE_FIXED$PMEMCHUNK_FIXED$POSCHUNK() > #1 01FB8D3C :0 ??() > #2 0040C51A :0 fpc_finalize() > #3 00000001 :0 ??() > #4 0040AD2A :0 SYSTEM_TOBJECT_$__CLEANUPINSTANCE() > #5 00520D80 :0 $MDLEXERCISE$_Ld37() > #6 00000001 :0 ??() > #7 01F0D888 :0 ??() > #8 00000000 :0 ??() > -------------------------------
I recently had a similarly strange error with almost exactly the same stack trace. After using a compiler and RTL that was compioled with full debug info and -O- it turned out that it happened during freeing of reference counted variables at the end of a procedure. Maybe the following might ring a bell: In my specific case my fault was to fill a dynamic array of PChar with pointers that pointed into a TStringList and then I passed a pointer to the first element of that array to a GTK function. Although this external function was supposed to make a deep copy of all my strings before it returns for some reason (and I still don't understand exactly why) passing these pointers to gtk (it was a drag-drop operation to the *same* application) was somehow able to corrupt FPC's memory and it crashed exactly at the moment when FPC heap manager tried to clean up some strings and dynamic arrays at the end. Interestingly (and this is the part I do not yet fully understand) while my misuse of these fragile PChar() was on the sending side of that drag/drop it actually crashed on the receiving side where the sent strings came out of GTK again (in the same application) in the LCL code when it tried to free a dynamic array of the *received* strings) Explicitly allocating some dedicated memory for my strings, making a copy and manually freeing it afterwards and not messing around with (and relying on) pointers deep into FPC managed reference counted memory solved this problem. _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
