Simon Ford / debug

Debug library for instrumentation a.k.a printf debugging

Dependents:   pyrocommander Projektni_zadatak_Analogni_sat ProjetOctopode

A debug library for instrumentation a.k.a printf debugging.

The aims of the library are:

  • Provide functions for instrumentation debugging that are simple and practical
  • Avoid people reinventing the wheel. Without a standard approach to debugging, each projects invents their own DBG, xprintf, dprintf type macros
    • And they are all slightly different, and possibly non-composable/compatible - consistency is good!
  • Provide support for statically selective debugging, such as enabling debug in a module or class (vs. all or nothing)
    • Allow debug to be included as part of library code bases, and only enabled when needed (rather than used during development, then commented out/removed)
    • Eliminate at compile time the calls/message strings of disabled debug, so instrumentation can be left in at zero cost
  • Allow options for dynamic debugging (can be programatically enabled)
  • Use stderr as debug stream, and ensure it can be re-routed to different stream devices

Usage

Basic debug

#include "mbed.h"
#include "debug.h"

int main() {    
    debug("Hello debug world");

    int v = 5;
    debug("Hello debug world, v = %d", v);
}

Conditional debug (static)

#include "mbed.h"
#include "debug.h"

#define DEBUG_MAIN 1

int main() {    
    debug(DEBUG_MAIN, "Hello debug world");

    int v = 5;
    debug(DEBUG_MAIN, "Hello debug world, v = %d", v);
}
  • Recommended define format: DEBUG_<module> or DEBUG_<module>_<aspect>
    • e.g. DEBUG_LCD, DEBUG_LCD_REDRAW

Conditional debug (dynamic)

#include "mbed.h"
#include "debug.h"

int main() {    
    bool debug_main = 0;
    debug(debug_main, "Hello debug world");
    debug_main = 1;
    int v = 5;
    debug(debug_main, "Hello debug world, v = %d", v);

    for(int i=0; i<10; i++) {
        debug(i > 7, "Debug something");
    }
}

Redirecting stderr

#include "mbed.h"
#include "debug.h"

LocalFileSystem local("local");

int main() {    
    freopen("/local/debug.txt", "w", stderr);
    debug("Hello debug file");
    fclose(stderr);
}

debug.h

Committer:
simon
Date:
2012-08-04
Revision:
3:b6e4a45bd418
Parent:
2:24afdea2d903

File content as of revision 3:b6e4a45bd418:

/* Copyright (c) 2012 mbed.org, MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 * and associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
#ifndef DEBUG_H
#define DEBUG_H

/** @file debug.h */

#ifndef NDEBUG

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

/** Output a debug message
 * 
 * @param format printf-style format string, followed by variables
 */
static inline void debug(const char *format, ...) {
    va_list args;
    va_start(args, format);
    vfprintf(stderr, format, args);
    va_end(args);
}

/** Conditionally output a debug message
 * 
 * @param condition output only if condition is true
 * @param format printf-style format string, followed by variables
 */
static inline void debug(bool condition, const char *format, ...) {
    if(condition) {
        va_list args;
        va_start(args, format);
        vfprintf(stderr, format, args);
        va_end(args);
    }
}

#else

static inline void debug(const char *format, ...) {}
static inline void debug(bool condition, const char *format, ...) {}

#endif

#endif