Logging

By default, libevpl logs to stderr in logfmt format.

The log output can be redirected to an application level function if desired.

Functions

evpl_set_log_fn

typedef void (*evpl_log_fn)(
    const char *level,
    const char *module,
    const char *srcfile,
    int         lineno,
    const char *fmt,
    va_list     argp);

typedef void (*evpl_flush_fn)(void);

void evpl_set_log_fn(
    evpl_log_fn   log_fn,
    evpl_flush_fn flush_fn);

Set custom logging callbacks.

Parameters:

• log_fn - Called for each emitted log message
• flush_fn - Called before crashing or asserting (optional, can be NULL)

Callback Parameters:

• level - Log level string (“ERROR”, “WARN”, “INFO”, “DEBUG”)
• module - Module name (“core”, “rdma”, “http”, etc.)
• srcfile - Source file where log originated
• lineno - Line number in source file
• fmt - Printf-style format string
• argp - Variable arguments list

Notes:

• The callback must be thread-safe if using multi-threaded event loops
• Logging may want to be buffered and flushed asynchronously to minimize performance impact
• Use vsnprintf() or similar to format the message
• Must be called before evpl_init() to capture all log messages.