Programming

/**
 * mydebug.h -- freeware
 */

/* Prevent mydebug.h from being included more than once */
#ifndef __MYDEBUG_H__
#define __MYDEBUG_H__

/* Makes these functions work even if you include and use this in a .cpp file */
#ifdef __cplusplus
extern "C" {
#endif

/* Don't call directly, use DEBUG_PRINT(("something")) macros */
void _debug_print(const char *cmdstr, ...);
void _info_print(const char *cmdstr, ...);

#ifdef __cplusplus
}
#endif

/**
 * INFO_PRINT always calls _info_print, even if it might NOT actually print anything,
 * so use it sparingly, it'll bloat the final program.
 */
#define INFO_PRINT(X) _info_print X

/**
 * Will ONLY be called when DEBUG is defined, should magically disappear
 * otherwise.  Use all you want, will not bloat non-DEBUG builds.
 */
#ifdef DEBUG
#define DEBUG_PRINT(X) _debug_print X
#else
#define DEBUG_PRINT(X)
#endif

#endif/*__MYDEBUG_H__*/

/**
 * mydebug.c -- freeware
 */
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include "mydebug.h"

void _debug_print(const char *cmdstr, ...)
{
  va_list ap;

  va_start(ap,cmdstr);
    vfprintf(stderr,cmdstr,ap);
  va_end(ap);
}

void _info_print(const char *cmdstr, ...)
{
  va_list ap;

  /**
   * When DEBUG is undefined, it checks for the DEBUG environment variable.
   * Otherwise, it always prints.
   */

#ifndef DEBUG
  if(getenv("DEBUG") == NULL) return;
#endif

  va_start(ap,cmdstr);
    vfprintf(stderr,cmdstr,ap);
  va_end(ap);
}

/**
 * debugtest.c -- freeware
 */
#include "mydebug.h"

int main()
{
  DEBUG_PRINT(("This should only print when DEBUG's defined in preprocessor %d\n",5));
  INFO_PRINT(("If DEBUG is defined, this always prints\n"));
  INFO_PRINT(("If DEBUG isn't defined, it only prints if DEBUG is in the environment\n"));
  return(0);
}