[SOLVED] How to undefine a define at commandline using GCC

Issue

How do I at compile time undefine a compiler macro using GCC? I tried some compile arguments to GCC, like rel="nofollow noreferrer">-D, but I can't get to see the "not defined" message.

#include <iostream>

#define MYDEF


int main(){

#ifdef MYDEF
  std::cout << "defined\n";
#else
  std::cout << "not defined\n";
#endif

}

Solution

You can use the -U option with GCC, but it won't undefine a macro defined in your source code. As far as I know, there isn't any way to do that.

Answered By - dcp

Answer Checked By - Marilyn (WPSolving Volunteer)