Macros

Macros are built on the #define preprocessor.

Normally a #define would look like:

	#define PI 3.142

But, a macro would look like this.

	#define SQUARE(x) x*x

The main difference is that the first example is a constant and the second is an expression. If the macro above was used in some code it may look like this:

        #define SQUARE(x)  x*x

        main()
        {
          int value=3;
          printf("%d \n", SQUARE(value));
        }

After preprocessing the code would become:

        main()
        {
          int value=3;
          printf("%d \n", value*value);
        }

Examples:

macro example.

Notes:

The value passed to SQUARE could have been an int float or double
Long macros can span multiple lines by using a \ followed by a newline (return).
If you are using gcc to compile your code, you can use the -E option to see the preprocessor output

Macros

Examples:

Notes:

See Also: