Compiler acts as if a preprocessor directive isn't defined - c++

Question

I have a header file and its cpp file (Error.h, Error.cpp). The cpp file performs a check on a preprocessor directive but it always fails.
Error.h:
/*
Optional macros:
AE_EXIT_AT_ERROR
AE_CONSOLE_WRITE_AT_ERROR
*/
#pragma once
extern void aeError(const char *str, int code=1);
extern void aeAssert(bool b, const char *failStr = "assertion failed");
Error.cpp:
#include "Error.h"
#include <stdexcept>
#ifdef AE_CONSOLE_WRITE_AT_ERROR
#include <iostream>
#endif
void aeError(const char *str, int code)
{
#ifdef AE_CONSOLE_WRITE_AT_ERROR
std::cout << str << std::endl;
#endif
throw std::runtime_error(str);
#ifdef AE_EXIT_AT_ERROR
std::exit(code);
#endif
}
void aeAssert(bool b, const char *failStr)
{
if(!b)
aeError(failStr);
}
main.cpp:
//define both macros:
#define AE_CONSOLE_WRITE_AT_ERROR
#define AE_EXIT_AT_ERROR
#include "Error.h"
//rest of code
//...
both std::cout << str << std::endl; and std::exit(code); don't get compiled (I checked it "manually", although they are also marked gray by the IDE, which is VS2010).
What might be the cause of this?

Answer 1

main.cpp and Error.cpp are different translation units. You define the macro only for main.cpp, not for Error.cpp.
You should either put your #define directives in a header file included by both .cpp files, or define these macros in project settings/makefile.