Implementation of All Exported Functions
Implementing the exported functions is the final step. The
    example function in first_module looks like this: 
    
| ZEND_FUNCTION(first_module)
{
    long parameter;
    if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", ¶meter) == FAILURE) {
        return;
    }
    RETURN_LONG(parameter);
} | 
    The function declaration is done
    using 
ZEND_FUNCTION, which corresponds
    to 
ZEND_FE in the function entry table (discussed
    earlier).
   
    After the declaration, code for checking and retrieving the function's
    arguments, argument conversion, and return value generation follows (more on
    this later).