Compared to ad-hoc if(printed) ... code this allows the user to disable it by adjusting the log level TODO: APIChanges & version bump Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> --- libavutil/log.c | 9 +++++++++ libavutil/log.h | 21 +++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/libavutil/log.c b/libavutil/log.c index 0a7b169bc0..57301d42d6 100644 --- a/libavutil/log.c +++ b/libavutil/log.c @@ -368,6 +368,15 @@ void av_log(void* avcl, int level, const char *fmt, ...) va_end(vl); } +void av_log_once(void* avcl, int initial_level, int subsequent_level, int *state, const char *fmt, ...) +{ + va_list vl; + va_start(vl, fmt); + av_vlog(avcl, *state ? subsequent_level : initial_level, fmt, vl); + va_end(vl); + *state = 1; +} + void av_vlog(void* avcl, int level, const char *fmt, va_list vl) { AVClass* avc = avcl ? *(AVClass **) avcl : NULL; diff --git a/libavutil/log.h b/libavutil/log.h index d9554e609d..9c14188a9c 100644 --- a/libavutil/log.h +++ b/libavutil/log.h @@ -233,6 +233,27 @@ typedef struct AVClass { */ void av_log(void *avcl, int level, const char *fmt, ...) av_printf_format(3, 4); +/** + * Send the specified message to the log once with the initial_level and then with + * the subsequent_level. By default, all logging messages are sent to + * stderr. This behavior can be altered by setting a different logging callback + * function. + * @see av_log + * + * @param avcl A pointer to an arbitrary struct of which the first field is a + * pointer to an AVClass struct or NULL if general log. + * @param initial_level importance level of the message expressed using a @ref + * lavu_log_constants "Logging Constant" for the first occurance. + * @param subsequent_level importance level of the message expressed using a @ref + * lavu_log_constants "Logging Constant" after the first occurance. + * @param fmt The format string (printf-compatible) that specifies how + * subsequent arguments are converted to output. + * @param state a variable to keep trak of if a message has already been printed + * this must be initialized to 0 before the first use. The same state + * must not be accessed by 2 Threads simultaneously. + */ +void av_log_once(void* avcl, int initial_level, int subsequent_level, int *state, const char *fmt, ...) av_printf_format(5, 6); + /** * Send the specified message to the log if the level is less than or equal -- 2.17.1