Deliberatly trigger a compilation error in Visual Studio 2008

Question

Hey,

Is there a way to deliberatly trigger a compilation error when a certain condition is satisfied on Visual Studio 2008?

Answer 1

In C++ you can use macros like the following to cause a compile time assert when a specified constant condition is false

#define COMPILE_ASSERT(expr) extern int __assertutil[(expr) != 0]

COMPILE_ASSERT(42 != 8);  // Fine
COMPILE_ASSERT(42 == 8);  // Error

This works because in the case that the expression is false it will have a constant value of 0. Arrays in C++ can not have a constant size of 0 and it leads to a compilation error.

Answer 2

You can use the #error pre-processor feature.

You use it like such:

#ifdef WIN32
    ... code for windows
#else
    #error only windows is supported
#endif

Answer 3

There are language specific pre-processor directives. In C#:

#define DEBUG class MainClass  {
    static void Main() 
    {
#if DEBUG
#error DEBUG is defined
#endif
    } 
}

From MSDN.

Answer 4

how about the compiler directive #error?

Answer 5

int i = (float)(5.0);

Answer 6

Thank you everyone for the answers, but I was looking for something more like a method that I could call to "decide" whether there's an error or not.

Thank you again.

Answer 7

I wonder if you're looking for a way to validate the source code before compilation. If so, you could use a pre-build step and fail it (exit with a code other than 0) to abort compilation.