#define macro vs Tiny functions

[Dave1024]

I just Read #define macros use instead of tiny functions...How i rewrite the following tiny fn:
by a #define macro

static long Multiply(long m,long n)
{
    return ( ((long long) m) * ((long long) n) ) >> 32; 
}

Plz comment....

[laserlight]

Read Stroustrup's answer to the FAQ: So, what's wrong with using macros?

[cilu]

Also see this FAQ: http://www.codeguru.com/forum/showthread.php?t=328273.

The worst part with macros is that being expanded at pre-compile time they are not helpful at all during debugging.

[JohnW@Wessex]

A demonstration of the perils of macro 'functions'
Try compiling this...

#define Multiply(a, b) ((a) * (b))

struct Test
{
    int Multiply(int a)
    {
        return (a * 2);
    }
};

int main()
{
    Test test;

    int result = test.Multiply(3);

    return 0;
}

Then try this...

int Multiply(int a, int b)
{
    return (a * b);
}

struct Test
{
    int Multiply(int a)
    {
        return (a * 2);
    }
};

int main()
{
    Test test;

    int result = test.Multiply(3);

    return 0;
}

If you really want macro style flexibility...

template <typename TReturn, typename T1, typename T2>
TReturn Multiply(T1 a, T2 b)
{
    return static_cast<TReturn>(a * b);
}