VA_ARGS 的用法.

#  Debug.h
int _MLPrintLog(int priority, const char *tag, const char *fmt,    ...)
#define MPL_LOG_PRI(priority, tag, fmt, ...)     _MLPrintLog(MPL_##priority, tag, fmt, ##__VA_ARGS__)

#debug.c

int _MLPrintLog (int priority, const char* tag, const char* fmt, ...)
{
    va_list args;
    int length;
    char buf[BUF_SIZE];

    va_start(args, fmt);
    length = vsprintf(buf, fmt, args);
    if (length <= 0) {
        va_end(args);
        return length;
    }
    va_end(args);
    return 0;
}