于 2012/7/4 23:46, niXman 写道:
> The following code gives the right result when compiled without
> defined __USE_MINGW_ANSI_STDIO macro.
> But, if __USE_MINGW_ANSI_STDIO macro is defined - the result is 6.
> Why?
>
> code:
> #include <stdio.h>
> int main() {
> wchar_t buf[2];
> int len = snwprintf(buf, sizeof(buf) / 2, L"world!");
> printf("%d\n", len);
> }
>
>
> Thanks.
>
>
Without the macro, it will hit the code
#if !defined (__USE_MINGW_ANSI_STDIO) || __USE_MINGW_ANSI_STDIO == 0
#pragma push_macro("snwprintf")
#pragma push_macro("vsnwprintf")
# undef snwprintf
# undef vsnwprintf
int __cdecl __ms_snwprintf (wchar_t * __restrict__ s, size_t n, const
wchar_t * __restrict__ format, ...);
int __cdecl __ms_vsnwprintf (wchar_t * __restrict__ , size_t, const
wchar_t * __restrict__ , va_list);
__mingw_ovr
int snwprintf (wchar_t * __restrict__ s, size_t n, const wchar_t *
__restrict__ format, ...)
{
int r;
va_list argp;
__builtin_va_start (argp, format);
r = _vsnwprintf (s, n, format, argp);
__builtin_va_end (argp);
return r;
}
It will call ms's _vsnwprintf
With the macro, it will hit the code
#ifndef __NO_ISOCEXT /* externs in libmingwex.a */
__mingw_ovr
/* __attribute__((__format__ (gnu_wprintf, 3, 4))) */
__MINGW_ATTRIB_NONNULL(3)
int snwprintf (wchar_t *__stream, size_t __n, const wchar_t *__format, ...)
{
register int __retval;
__builtin_va_list __local_argv; __builtin_va_start( __local_argv,
__format );
__retval = __mingw_vsnwprintf( __stream, __n, __format, __local_argv );
__builtin_va_end( __local_argv );
return __retval;
}
It will call __mingw_vsnwprintf
Maybe someone can explain it here.
--
Best Regards,
xunxun
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