How to resolve variable conflicts in header files?

Question

I am writing an adaptive step size update algorithm in OpenSees (an opensource earthquake engineering simulation project written majorly in visual studio c++). I am facing a conflict between two variables having the same name in two different header files (namely, windef.h and steelz01.h). I need a way to resolve this conflict.

I am using gnuplot-iostream.h in my project, I am facing this conflict only when I include this header file, otherwise there is no conlfict, code is builidng perfectly.

Basically gnuplot-iostream.h is calling windows.h, which is further calling windef.h. I have added include gauards in steelz01.h file, but it did not resolve the issue.

When I change the varaibale name in steelz01.h to a different name, then also the code is perfectly building. No ISSUE found. But, I don't want to channge the name of the variable in steelz01, it has serious repercussions.

I am including header files like this

#include "gnuplot-iostream.h"
#include <SteelZ01.h>

This is how the variable SIZE is defined in steelz01

#define LOOP_NUM_LIMIT               30
const int SIZE = LOOP_NUM_LIMIT; //limit of array number

and in windef.h, it is defined like this

typedef struct tagSIZE
{
    LONG        cx;
    LONG        cy;
} SIZE, *PSIZE, *LPSIZE;

typedef SIZE               SIZEL;
typedef SIZE               *PSIZEL, *LPSIZEL;

Visual Studio 2017 is throwing this error,

1>c:\program files (x86)\windows kits\8.1\include\shared\windef.h(190): error C2378: 'SIZE': redefinition; symbol cannot be overloaded with a typedef

1>e:\phd working folder\0_ops_github\src\material\nd\reinforcedconcreteplanestress\steelz01.h(17): note: see declaration of 'SIZE'

I am expecting a way to resolve this conflict and a successful build.

Answer 1

I would suggest you to put include statement in namespace,

namespace ABC
{
    #include "gnuplot-iostream.h"
}

namespace PQR
{
   #include <SteelZ01.h>
}

Call:

ABC::SIZE
PQR::SIZE

This will not change any code of existing libraries. However, author of library using common names hence suggest him to keep common name under namespace to reduce any conflict.