av_printf_format 156 libavformat/rtpproto.c static av_printf_format(3, 4) void url_add_option(char *buf, int buf_size, const char *fmt, ...) av_printf_format 161 libavutil/attributes.h # define av_printf_format(fmtpos, attrpos) __attribute__((__format__(__printf__, fmtpos, attrpos))) av_printf_format 164 libavutil/attributes.h # define av_printf_format(fmtpos, attrpos)