Subroutines

Perl defines subroutines in the following form:

 sub SUBNAME { 
		STATEMENTS; 
	}

Subroutines are invoked in this way:

	&SUBNAME(arg1,arg2,etc); 
	# - or - (if the subroutine takes no arguments. 
	&SUBNAME; 
	# return values are used just like any other value  
	$returnvalue = &SUBNAME(@values);

Example

	# define an error  routine: 
	sub error { 
		($message) = @_; 
		print("<b>ERROR:<b>", 
		$message, 
		"<p>Contact the author of the previous page for assistance\n"); 
		exit(0); 
	} 
	if ( ! $recipient ) { 
		# the form did not have a to field 
		# modify this text appropriately 
		&error("No Return Address"); 
	}