log.h

#ifndef _LOG_H_
#define _LOG_H_

/* Windows before 10 does not understand ASCII color codes. */
#if defined(__WINDOWS__) && defined(__COLORFUL__)
# undef __COLORFUL__
#endif

/* ANSI escape code for colors. */
#ifdef __COLORFUL__
# define NRM  "\x1B[0m"
# define RED  "\x1B[31m"
# define GRN  "\x1B[32m"
# define YEL  "\x1B[33m"
# define MAG  "\x1B[36m"
# define WHT  "\x1B[37m"
#else
# define NRM
# define RED
# define GRN
# define YEL
# define MAG
# define WHT
#endif /* __COLORFUL__ */

#ifndef __LOG__
# define __log(lvl, flag, ...) do {} while(0)
#else

# define LDEBUG NRM
# define LINFO GRN
# define LWARN YEL
# define LFATAL RED

# define LOG_D 0x1
# define LOG_I 0x2
# define LOG_W 0x4
# define LOG_F 0x8

# if defined(__DEBUG__)
#  define LOG_LVL LOG_D
# elif defined(__INFO__)
#  define LOG_LVL LOG_I
# elif defined(__FATAL__)
#  define LOG_LVL LOG_F
# else
#  define LOG_LVL LOG_W
# endif
# define __log(lvl, flag, fmt, ...) do {   \
     if(lvl >= LOG_LVL) {   \
         printf("[COMDB2-ODBC][%s" NRM "][" \
                 MAG "%s" NRM"][" MAG "%s" NRM "] at line " MAG "%d" NRM ": ", flag, __FILE__ , __func__, __LINE__); \
         printf(fmt, ##__VA_ARGS__);   \
         printf("\n");  \
     }  \
} while(0)
#endif /* __LOG__ */

# define __debug(fmt, ...) __log(LOG_D, LDEBUG "DEBUG", fmt, ## __VA_ARGS__)
# define __info(fmt, ...) __log(LOG_I, LINFO "INFO", fmt, ## __VA_ARGS__)
# define __warn(fmt, ...) __log(LOG_W, LWARN "WARN", fmt, ## __VA_ARGS__)
# define __fatal(fmt, ...) __log(LOG_F, LFATAL "FATAL", fmt, ## __VA_ARGS__)

#ifdef _WIN32
static inline void win32msgbox(char *fmt, ...)
{
    char msg[1024];
    va_list args;
    va_start(args, fmt);
    vsnprintf(msg, 1024, fmt, args);
    va_end(args);

	MessageBox(
        NULL,
		msg,
        "Log",
        MB_OK
    );
}
#endif
#endif