Some C debug macros

debug.h

/*
 * A collection of three macros for debugging: DEBUG, WARN, ERROR.
 *
 * All three take a variable number of arguments and match the format of the
 * printf family of functions. For example:
 *     WARN("The value of n is %d\n", n);
 *
 * All three are disabled if NDEBUG is defined, just like assert.
 *
 * by Miles Glapa-Grossklag, 2021
 */
#ifndef DEBUG_H
#define DEBUG_H

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

// Begin an escape sequence.
#define _DEBUG_COLOR "\033["

// End an escape sequence.
#define _DEBUG_END "m"

#define _DEBUG_RESET "0"
#define _DEBUG_RED "91"
#define _DEBUG_GREEN "92"
#define _DEBUG_YELLOW "93"

#ifdef NDEBUG

// If NDEBUG is defined, the macros should do nothing.
#define DEBUG(...) ((void)((__VA_ARGS__))
#define WARN(...) ((void)((__VA_ARGS__))
#define ERROR(...) ((void)((__VA_ARGS__))

#else

#define DEBUG(...)                                                             \
  do {                                                                         \
    fprintf(stderr, _DEBUG_COLOR _DEBUG_GREEN _DEBUG_END                       \
            "[DEBUG]" _DEBUG_COLOR _DEBUG_RESET _DEBUG_END " ");               \
    fprintf(stderr, __VA_ARGS__);                                              \
  } while (0)

#define WARN(...)                                                              \
  do {                                                                         \
    fprintf(stderr, _DEBUG_COLOR _DEBUG_YELLOW _DEBUG_END                      \
            "[WARNING]" _DEBUG_COLOR _DEBUG_RESET _DEBUG_END " ");             \
    fprintf(stderr, __VA_ARGS__);                                              \
  } while (0)

#define ERROR(...)                                                             \
  do {                                                                         \
    fprintf(stderr, _DEBUG_COLOR _DEBUG_RED _DEBUG_END                         \
            "[ERROR]" _DEBUG_COLOR _DEBUG_RESET _DEBUG_END " ");               \
    fprintf(stderr, __VA_ARGS__);                                              \
  } while (0)

#endif

#endif

example.c

#include "debug.h"

int main(void) {
  DEBUG("I'm some debug info\n");    
  WARN("I'm a warning\n");
  ERROR("I'm an error!\n");
  return 0;
}