remove debug strings in release build

Question

I use a LOG_DEBUG function to print debug information to the screen. I used a #define _DEBUG to disable LOG_DEBUG function by defining _DEBUG FLAG in compile time (release time). but linux strings commands of release build app still shows debug strings which exists in the compiled app. so what is the alternatives to eliminate arguments of LOG_DEBUG?

#ifdef _DEBUG
#define LOG_DEBUG(fmt, ...) printf("[D][%s:%d %s]", __FILE__, __LINE__, __FUNCTION__, ##__VA_ARGS__)
#else
#define LOG_DEBUG(fmt, ...)
#endif


LOG_DEBUG("this is a debug string");     // "this is a debug string" exists in app release build yet

the compiler I use: ARM/Thumb C/C++ Compiler, RVCT3.1 [Build 569]

optimization: -O3

Please edit your question to include the compiler name and version. Have you tried changing the optimization settings? — r3mainer, Jun 01 '17 at 21:31
I guess *one* way would be to surround **each** debug with an `#ifdef`, but I assume you don't want to do that ;) — Jeeter, Jun 01 '17 at 21:35
there's a huge number of function calls, I'm looking for a cleaner way — jafar, Jun 01 '17 at 21:37
What you are currently doing is the standard way of handling this situation. In a build that doesn't contain _DEBUG then that string should disappear. Why not generate the .i file and see if the string exists there. — Neil, Jun 02 '17 at 14:36

score 3 · Accepted Answer · answered Jun 01 '17 at 21:47

You could try using stringification:

#include <stdio.h>

#define _DEBUG

#ifdef _DEBUG
#define LOG_DEBUG(str) do { printf("[D][%s:%d %s] ", \
                               __FILE__, \
                               __LINE__, \
                               __FUNCTION__); \
                            puts(#str); } while(0)
#else
#define LOG_DEBUG(str)
#endif

int main() {
  LOG_DEBUG(this is a debug string);
  return 0;
}

Note: I tested this in clang, which doesn't exhibit the behaviour you described.

maybe this is just a armcc issue – jafar Jun 01 '17 at 21:49 — jafar, Jun 01 '17 at 21:49

remove debug strings in release build

1 Answers1