Logging macros for ISO C

logging.h

/*****************
**  Vit Pavlik  **
**   xpavli0a   **
**    251301    **
*****************/

/**
 * Logging macros
 */

 #ifndef _U_T_I_L_S_H_
 #define _U_T_I_L_S_H_

 #include <stdio.h>   // fprintf
 #include <string.h>  // strcmp

 /* log levels */
 #define DEBUG 0
 #define INFO 1
 #define WARNING 2
 #define ERROR 3
 #define FATAL 4  // fatal error

 #ifndef NDEBUG

 /* use colors? tip: use when outputting to terminal, don't use when outputting
 to file */
 #define UTILS_USE_COLORS 1

 /* https://gist.github.com/RabaDabaDoba/145049536f815903c79944599c6f952a */
 #if UTILS_USE_COLORS
 #define BLK "\033[0;30m"
 #define RED "\033[0;31m"
 #define GRN "\033[0;32m"
 #define YEL "\033[0;33m"
 #define BLU "\033[0;34m"
 #define MAG "\033[0;35m"
 #define CYN "\033[0;36m"
 #define WHT "\033[0;37m"
 #define RST "\033[0m"  // reset
 #else  // if UTILS_USE_COLORS
 #define BLK ""
 #define RED ""
 #define GRN ""
 #define YEL ""
 #define BLU ""
 #define MAG ""
 #define CYN ""
 #define WHT ""
 #define RST ""  // reset
 #endif  // if UTILS_USE_COLORS


 #define utils_prefix(lvl) ( \
     lvl == DEBUG   ? "DEBUG"   : \
     lvl == INFO    ? WHT "INFO"    RST : \
     lvl == WARNING ? YEL "WARNING" RST : \
     lvl == ERROR   ? RED "ERROR"   RST : \
     lvl == FATAL   ? MAG "FATAL"   RST : \
     "unknown-log-level" \
 )

 /*-----------------------------LOGGING----------------------------------------*/

 /* set to 1 if you want to log the function name */
 #define LOG_FN_NAME 1

 /* spaces to pad the function name */
 #define FN_NAME_PAD 15


 /* implicit log level (can be overridden by -DLOGLEVEL=lvl compiler flag) */
 #ifndef LOGLEVEL
 #define LOGLEVEL DEBUG
 #endif  // #ifndef LOGLEVEL

 #if LOG_FN_NAME

 /* logs plain string (like puts) or does nothing if NDEBUG is defined */
 #define log(lvl, msg) do { \
     if (lvl >= LOGLEVEL) { \
         fprintf(stderr, "%s: ", utils_prefix(lvl)); \
         fprintf(stderr, __FILE__ ":%04d (%-*s): %s\n", __LINE__, \
         FN_NAME_PAD, __func__, msg); \
     } \
 } while (0)

 /* logs format (like printf) or does nothing if NDEBUG is defined */
 #define logf(lvl, msg, ...) do { \
     if (lvl >= LOGLEVEL) { \
         fprintf(stderr, "%s: ", utils_prefix(lvl)); \
         fprintf(stderr, __FILE__ ":%04d (%-*s): " msg "\n", \
         __LINE__, FN_NAME_PAD, __func__, __VA_ARGS__); \
     } \
 } while (0)

 #else  // if LOG_FN_NAME

 /* logs plain string (like puts) or does nothing if NDEBUG is defined */
 #define log(lvl, msg) do { \
     if (lvl >= LOGLEVEL) { \
         fprintf(stderr, "%s: ", utils_prefix(lvl)); \
         fprintf(stderr, __FILE__ ":%04d: %s\n", __LINE__, msg); \
     } \
 } while (0)

 /* logs format (like printf) or does nothing if NDEBUG is defined */
 #define logf(lvl, msg, ...) do { \
     if (lvl >= LOGLEVEL) { \
         fprintf(stderr, "%s: ", utils_prefix(lvl)); \
         fprintf(stderr, __FILE__ ":%04d: " msg "\n", __LINE__, \
                 __VA_ARGS__); \
     } \
 } while (0)

 #endif  // if LOG_FN_NAME

 /*----------------------------------------------------------------------------*/

 #else  // ifndef NDEBUG

 #define log(lvl, msg) {}
 #define logf(lvl, msg, ...) {}


 #endif  // ifndef NDEBUG
 #endif  // ifndef _U_T_I_L_S_H_