t.h: #pragma GCC system_header
extern __inline __attribute__ ((__always_inline__)) char * __attribute__ ((__nothrow__)) blabla (char *__restrict __dest, __const char *__restrict __src) { return __builtin___strcpy_chk (__dest, __src, __builtin_object_size (__dest, 2 > 1)); } t.c: #include "t.h" char buf[6]; int main(int argc, char **argv) { blabla(buf,"hello "); return 0; } no longer warns with GCC 4.4 because blabla is in a system-header (blabla == strcpy, but 4.3 folds that to memcpy which we also do not warn, 4.4 doesn't do that folding). -- Summary: [4.4 Regression] -D_FORTIFY_SOURCE=2 no longer warns with new glibc headers Product: gcc Version: 4.4.0 Status: UNCONFIRMED Keywords: diagnostic Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rguenth at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39272