c define multiline macro?

Question

#define DEBUG_BREAK(a)\\
    if ((a)) \\
{\\
    __asm int 3;\\
}

I have defined a macro as above, and try to use it

#include \"test_d         


        

Answer 1

The macro

#define DEBUG_BREAK(a)\
    if ((a)) \
    __asm int 3;

works fine but

#define DEBUG_BREAK(a)\
    if ((a)) \
{\
    __asm int 3;\
}

doesn't! And I think anyone could guess why!! The new line operator is the problem making guy!

It takes

 __asm int 3;\
}

as

__asm int 3; }

where ; comments out what follows it (in assembly). So we will miss a } then.

Answer 2

#define DEBUG_BREAK(a)\
if ((a)) \
{\
    __asm \
    { \
        int 3;\
    } \
}

Or.... (since you are on Windows, just use the DebugBreak function...)

#define DEBUG_BREAK(a) {if ((a)) DebugBreak();}

Answer 3

That's weird, but getting {int 3} into brackets helps. And combining macro into singleliner doesn't. So it should be something about assembly, not the multilining.

Answer 4

Please try this

#define DEBUG_BREAK(a)\
    if ((a)) \
    __asm int 3;

Answer 5

Rewrite it as an inline function:

inline void DEBUG_BREAK(bool b)
{
    if (b) 
    {
        __asm int 3
    }
}

You may want to replace __asm int 3 with DebugBreak(), as that is the official MS function to do this.

Answer 6

Check there is no white space after each backslash. I often fall for this.

You might even need a single space before the backslash.