Macro on cpp library included is ruining the rest of the codebase - c++

Question

I'm working on an application that includes this library, let's call Snap.h.
I found that compilation fails if Snap.h is not the last on the includes statements. And on closer look, I find this code in a header file included by Snap.h
#define Try try {
#define Catch } catch (PExcept Except){ErrNotify(Except->GetMsgStr());}
#define CatchFull } catch (PExcept Except){ErrNotify(Except->GetStr());}
#define CatchAll } catch (...){}
Basically this lets try and catch blocks to be used as statements, like so
Try;
<some code>
Catch;
You can see how this is an issue, these generic macros collide with other libraries very easily.
Unfortunately this is tens of thousands of lines of very complicated code and the application I'm working on is built around this library. Its not easily changed.
Cpp is not my strong suit, is there a way to limit the effects of macros in an include?

Answer 1

I not a big fan of #undef things, because you never now what other bad stuff can slumber in that big header. I prefer isolating it in a "compilation barrier" i.e. only including it in a separate wrapper translation unit, which only redefines and forwards what you need. In the following example Snap.h redefines BULLSHIT to std::terminate, but as you can try, main.cpp can use the function in Snap.h without its version of BULLSHIT:
/*! #file main.cpp
*/
#include <iostream>
#define BULLSHIT
#include "snap_wrapper.h"
int main() {
BULLSHIT
std::cout << wrapper::nice_function() << "\n";
}
/*! #file Snap.h
*/
#ifndef UNTITLED5_SNAP_H
#define UNTITLED5_SNAP_H
#define BULLSHIT std::terminate();
int nice_function() {
return 42;
}
#endif //UNTITLED5_SNAP_H
/*! #snap_wrapper.h
*/
#ifndef UNTITLED5_SNAP_WRAPPER_H
#define UNTITLED5_SNAP_WRAPPER_H
namespace wrapper{
int nice_function();
}
#endif //UNTITLED5_SNAP_WRAPPER_H
/*! #file snap_wrapper.c
*/
#include "snap_wrapper.h"
#include "Snap.h"
namespace wrapper {
int nice_function() {
return ::nice_function();
}
}