Debugging question

if I have the following function

Code:

inline void SHOWERROR(char *str)
{
    #ifdef _DEBUG
    char buf[1024];
    char file[] = __FILE__;
    int line = __LINE__;
    sprintf(buf, "File: %s\nLine: %d\n%s", file, line, str);
    MessageBox(0, buf, "Error", 0);
    #endif
}

Assuming _DEBUG was not defined, would the compiler generate any extra instruction in this if statement?

Code:

    if (!(memcpy(pDest, pSource, size) ) )
    {
        SHOWERROR("Error Message");
    }

or would it be better to use something like this

Code:

#define SHOWERROR(s)   { char buf[1024];                                      \
                         char file[] = __FILE__;                              \
                         int line = __LINE__;                                 \
                         sprintf(buf, "File: %s\nLine: %d\n%s",file,line,s);  \
                         MessageBox(0, buf, "Error", 0); }
...
    if (!(memcpy(pDest, pSource, size) ) )
    {
        #ifdef _DEBUG
        SHOWERROR("Error Message");
        #endif
    }

An empty inline function should be completely eliminated by the compiler.
Your first approach seems fine to me.

I'm not sure if the compiler eliminates it or not, but I usually write debug functions like this:

Code:

#ifdef _DEBUG
    void DBG_FUNC( int param )
    {
        ...
    }
#else
#   define DBG_FUNC( param )
#endif