Question

In one of the C source code files I found the following line (macro):

#define USE(x) (x) = (x)

It is used like this:

int method(Obj *context)
    {
    USE(context);
    return 1;
    }

After googling for it, I found the following description:

// Macro to get rid of some compiler
warnings

Could you please tell me more about this macro?

Thanks for your answers!

Answer 1

Some compilers complain when variables are never actually used for anything. for instance:

int main(int argc, char **argv) {
  return 0;
}

Gives:

Output from llvm C/C++/Fortran front-end (llvm-gcc)

/tmp/webcompile/_7618_1.c: In function 'main':
/tmp/webcompile/_7618_1.c:9: warning: unused parameter 'argc'
/tmp/webcompile/_7618_1.c:9: warning: unused parameter 'argv'

Queerly, I can just get rid of those warnings using your macro:

#define USE(x) (x) = (x)


int main(int argc, char **argv) {
  USE(argc); /* get rid of warnings */
  USE(argv); /* get rid of warnings */
  return 0;
}