Question

I have a structure defined in a header file called data.h.

I am including data.h in myfile.c.

In the structure, I have part of the variables blocked off with:

#ifndef TEST
 int x;
#endif

and in myfile.c I have:

#ifdef TEST
localx++;
#else
mystruct.x++; //<-compiler complains on this line when compiling
#endif

When I try to compile with -DTEST I get a compiler complaining that mystruct type does not containing a field called x. What is up with this?

I don’t have a C compiler handy, so here is what I just typed up:

in data.h

typdef struct {

#ifndef TEST
int x;
#endif
int y;
} coords;

in myfile.c

#include "data.h" 
static coords coord1;
int localx;

int main( ) 
{ 
#ifdef TEST
  localx = 1;
#else
  coord1.x = 1;
#endif

  coord1.y = 2;
  printf("%i\n", coord1.x);
  printf("%i\n", coord1.y);
  printf("%i\n", localx);

  return 0; 
} 

This compiles when I type cc myfile.c but not with cc myfile.c -DTEST
I am using the MIPSPro C compiler referenced here.

Answer 1

You most recent edit (which may well be different by the time anyone reads this) will have a problem in the section that has a bunch of printf() statements. The line:

 printf("%i\n", coord1.x);

is referencing the x member of the struct regardless of the setting of the TEST preprocessor macro. It needs to be inside a conditional compilation section too in order to compile correctly (rather not compile at all) when the x member doesn’t exist.