Logging API for C scripts

Expected behavior of the wanted feature

Similar to the mp.msg module for Lua scripts which allows sending log messages, we should implement a similar API that can be used by C scripts. I have checked client.h but could not find any function definitions that would allow this.

Alternative behavior of the wanted feature

Manually printing log messages to stderr. This not only looks out-of-line, but will also clobber term-osd.

Log File

No response

Sample Files

The API could perhaps look something like this:

typedef enum mpv_log_level {
    MPV_TRACE,
    MPV_DEBUG,
    MPV_VERBOSE,
    MPV_INFO,
    MPV_WARN,
    MPV_ERROR,
    MPV_FATAL
} mpv_log_level;

// Send a string log message
void mpv_msg_log(mpv_log_level level, const char *msg);

// Use format strings (this could also just be `mpv_msg_log`)
void mpv_msg_logf(mpv_log_level level, const char *fmt, ...);

// Perhaps also shorthands for log levels such as `mpv_msg_info`.

Start by comparing the existing Lua mp.msg module with the C scripting API described in client.h. Define the supported log levels and message or format-string behavior, then verify that C-script logging reaches the normal log handling without clobbering term-osd.