Quicklog: For when printf isn't enough but a full logging library is too much

quicklog.h

//quicklog.h
//include it, and just loginfo("hello, %s", "world");
//MIT licence

#include <stdio.h>
#include <time.h>

#ifndef QUICKLOG_H
#define QUICKLOG_H

/* The different log levels */
enum log_level {
	LOGLVL_DEBUG, /* Debugging information. */
	LOGLVL_INFO,  /* Informational messages that might be useful to users; progress information, etc */
	LOGLVL_WARN,  /* A warning that something might be wrong with the user's input. */
	LOGLVL_ERROR, /* Something is wrong with the user's input; cannot continue. */
	LOGLVL_FIRE   /* Something is wrong with our program or the OS; malloc(2) returning null, etc */
};

/* LOGLVL: Logging messages below this level will not be printed. */
#define LOGLVL LOGLVL_DEBUG

/* LOG_TARGET: Where logs go */
#define LOG_TARGET stderr

#define LOG_FORMAT "%-10llu: %-7s\t%s\n"
#define LOGLINEBUFLEN 60

/* Check loglevel at logtime on top of compiled loglevel? */
#define CHECK_LOGLEVEL_AT_RUNTIME 0
enum log_level runtime_log_level = LOGLVL;

char loglinebuf[LOGLINEBUFLEN];
time_t loglinetime;

#define quicklog(...) snprintf(loglinebuf, LOGLINEBUFLEN, __VA_ARGS__); time(&loglinetime);

#define output_loglinebuf(levelname) fprintf(LOG_TARGET, LOG_FORMAT, (long long)loglinetime, levelname, loglinebuf)


#if CHECK_LOGLEVEL_AT_RUNTIME
/* Check loglevel at runtime */
#if LOGLVL <= LOGLVL_DEBUG
#define logdebug(...) if (runtime_log_level >= LOGLVL_DEBUG) {quicklog(__VA_ARGS__); output_loglinebuf("DEBUG");}
#else
#define logdebug(...)
#endif

#if LOGLVL <= LOGLVL_INFO
#define loginfo(...) if (runtime_log_level >= LOGLVL_INFO) {quicklog(__VA_ARGS__); output_loglinebuf("INFO");}
#else
#define loginfo(...)
#endif

#if LOGLVL <= LOGLVL_WARN
#define logwarn(...) if (runtime_log_level >= LOGLVL_WARN) {quicklog(__VA_ARGS__); output_loglinebuf("WARNING");}
#else
#define logwarn(...)
#endif

#if LOGLVL <= LOGLVL_ERROR
#define logerror(...) if (runtime_log_level >= LOGLVL_ERROR) {quicklog(__VA_ARGS__); output_loglinebuf("ERROR");}
#else
#define logerror(...)
#endif

#if LOGLVL <= LOGLVL_FIRE
#define logfire(...) if (runtime_log_level >= LOGLVL_FIRE) {quicklog(__VA_ARGS__); output_loglinebuf("FIRE!!!");}
#else
#define logfire(...)
#endif

#else
/* Don't check loglevel at runtime */

#if LOGLVL <= LOGLVL_DEBUG
#define logdebug(...) quicklog(__VA_ARGS__); output_loglinebuf("DEBUG")
#else
#define logdebug(...)
#endif

#if LOGLVL <= LOGLVL_INFO
#define loginfo(...) quicklog(__VA_ARGS__); output_loglinebuf("INFO")
#else
#define loginfo(...)
#endif

#if LOGLVL <= LOGLVL_WARN
#define logwarn(...) quicklog(__VA_ARGS__); output_loglinebuf("WARNING")
#else
#define logwarn(...)
#endif

#if LOGLVL <= LOGLVL_ERROR
#define logerror(...) quicklog(__VA_ARGS__); output_loglinebuf("ERROR")
#else
#define logerror(...)
#endif

#if LOGLVL <= LOGLVL_FIRE
#define logfire(...) quicklog(__VA_ARGS__); output_loglinebuf("FIRE!!!")
#else
#define logfire(...)
#endif

#endif
#endif