On Thu, 2012-07-26 at 07:32 +0200, Luca Barbato wrote:
> +int snprintf(char *buffer, size_t bufsize, const char *fmt, ...)
> +{
> + va_list ap;
> + int ret;
> +
> + if ((int)bufsize <= 0) return -1;
bufsize == 0 is valid.
> + ret = vsnprintf(buffer, bufsize-1, fmt, ap);
IIRC MSVC (or the C library) does not support all standard format
modifiers, so unless this vsnprintf comes from elsewhere, you need more
to get fully working printf formatting.
I'm not sure if this is working in current MinGW-compiled Libav either -
you need to set __USE_MINGW_ANSI_STDIO at least; the problem cases
probably occur rarely enough that problems may go unnoticed.
> + if (ret < 0) {
> + buffer[bufsize - 1] = '\0';
> + ret = bufsize - 1;
Wrong return value. It's supposed to be the number of bytes the output
would take without restriction. The following pattern is supposed to
work:
int r = snprintf(NULL, 0, ...);
if (r < 0) return -1;
char *p = malloc(r + 1);
snprintf(p, r, ...);
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