https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80807
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Status|UNCONFIRMED |NEW Last reconfirmed| |2017-05-18 Component|c |middle-end Known to work| |7.1.0 Ever confirmed|0 |1 Known to fail| |5.4.0, 6.3.0 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- I get with GCC 7: > gcc-7 t.c -O3 -D_FORTIFY_SOURCE=2 -Wall -S t.c: In function ‘test’: t.c:6:29: warning: ‘__builtin___sprintf_chk’ writing a terminating nul past the end of the destination [-Wformat-overflow=] sprintf(buf, "%c%c", a, b); ^ In file included from /usr/include/stdio.h:936:0, from t.c:1: /usr/include/bits/stdio2.h:33:10: note: ‘__builtin___sprintf_chk’ output 3 bytes into a destination of size 2 return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ __bos (__s), __fmt, __va_arg_pack ()); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ confirmed with GCC 5 and 6.