ForkThe following toy program:
#include <inttypes.h>
#include <stdio.h>
int main (void)
{
unsigned char c = 0x12;
char buf[3];
snprintf (buf, 3, "%02" SCNx8, c);
puts (buf);
return 0;
}
generates the following diagnostics:
d:\usr\eli>gcc -Wall -o pt.exe pt.c
pt.c: In function 'main':
pt.c:8:21: warning: unknown conversion type character 'h' in format [-Wformat=]
snprintf (buf, 3, "%02" SCNx8, c);
^~~~~
In file included from pt.c:1:
d:\usr\include\inttypes.h:246:17: note: format string is defined here
#define SCNx8 "hhx"
^
pt.c:8:21: warning: too many arguments for format [-Wformat-extra-args]
snprintf (buf, 3, "%02" SCNx8, c);
^~~~~
The warning goes away if I replace snprintf with __mingw_snprintf. It
also goes away if I add the -fno-builtin-snprintf compiler switch.
So it looks like the __mingw_printf__ attribute fails to cause the
compiler to recognize that our snprintf does support %hh?
This is with GCC 8.2.0 and MinGW runtime 5.2.1. I see the same
warning with GCC 7.3.0.
Am I doing something wrong?