stringbuffer_avprintf()

static int stringbuffer_avprintf ( stringbuffer_t *  s, const char *  fmt, va_list  ap  )

static

Appends a formatted string to the current string buffer, using the format and argument list provided.

Returns -1 on error, check errno for reasons, documented in the printf man page.

Definition at line 196 of file stringbuffer.c.

{
        int maxlen = (s->capacity - (s->str_end - s->str_start));
        int len = 0; /* Length of the output */
        va_list ap2;
 
        /* Make a copy of the variadic arguments, in case we need to print twice */
        /* Print to our buffer */
        va_copy(ap2, ap);
        len = vsnprintf(s->str_end, maxlen, fmt, ap2);
        va_end(ap2);
 
        /* Propogate errors up */
        if ( len < 0 )
                #if defined(__MINGW64_VERSION_MAJOR)
                va_copy(ap2, ap);
                len = _vscprintf(fmt, ap2);
                va_end(ap2);
                #else
                return len;
                #endif
 
        /* We didn't have enough space! */
        /* Either Unix vsnprint returned write length larger than our buffer */
        /*     or Windows vsnprintf returned an error code. */
        if ( len >= maxlen )
        {
                stringbuffer_makeroom(s, len + 1);
                maxlen = (s->capacity - (s->str_end - s->str_start));
 
                /* Try to print a second time */
                len = vsnprintf(s->str_end, maxlen, fmt, ap);
 
                /* Printing error? Error! */
                if ( len < 0 ) return len;
                /* Too long still? Error! */
                if ( len >= maxlen ) return -1;
        }
 
        /* Move end pointer forward and return. */
        s->str_end += len;
        return len;
}

References pixval::fmt, s, and stringbuffer_makeroom().

Referenced by stringbuffer_aprintf().

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