https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79879
--- Comment #11 from Lukas Wyporek <wyporek at poczta dot onet.pl> --- When "%hhu" format is literal, and -Wall parameter is used there are correct warnings - for example: main.c:11:23: warning: unknown conversion type character 'h' in format [-Wformat =] sscanf(buffer, "%hhu", &userNumber); =================================================== But when format is a pointer to string buffer, there are no warnings, even if I compile with that parameters: gcc main.c -o main.exe -Wall -Wextra -Wformat-security Best regards,