log.c

A simple logging library implemented in C99

Usage

log.c and log.h should be dropped into an existing project and compiled along with it. The library provides 6 function-like macros for logging:

log_trace(const char *fmt, ...);
log_debug(const char *fmt, ...);
log_info(const char *fmt, ...);
log_warn(const char *fmt, ...);
log_error(const char *fmt, ...);
log_fatal(const char *fmt, ...);

Each function takes a printf format string followed by additional arguments:

log_trace("Hello %s", "world")

Resulting in a line with the given format printed to stderr:

20:18:26 TRACE src/main.c:11: Hello world

log_set_quiet(int enable)

Quiet-mode can be enabled by passing 1 to the log_set_quiet() function. While this mode is enabled the library will not output anything to stderr, but will continue to write to the file if one is set.

log_set_level(int level)

The current logging level can be set by using the log_set_level() function. All logs below the given level will be ignored. By default the level is LOG_TRACE, such that nothing is ignored.

log_set_fp(FILE *fp)

A file pointer where the log should be written can be provided to the library by using the log_set_fp() function. The data written to the file output is of the following format:

2047-03-11 20:18:26 TRACE src/main.c:11: Hello world

log_set_lock(log_LockFn fn)

If the log will be written to from multiple threads a lock function can be set. The function is passed a udata value (set by log_set_udata()) and the integer 1 if the lock should be acquired or 0 if the lock should be released.

LOG_USE_COLOR

If the library is compiled with -DLOG_USE_COLOR ANSI color escape codes will be used when printing.

License

This library is free software; you can redistribute it and/or modify it under the terms of the MIT license. See LICENSE for details.