Re: Parenthesize macros in xfs

[Kyle Moffett <mrmacman_g4@mac.com>]

On Mar 26, 2006, at 07:19:14, Måns Rullgård wrote:
> A double semicolon can cause all sorts of hard to debug problems.   
> Consider this:
>
> #define foo() bar();
> /* ... */
> if(x)
>     foo();
> else
>     baz();
>
> This will expand to syntactically invalid code because of the extra  
> semicolon.

More generically, the code "do { [...] } while(0)" can _always_ be  
substituted for the code "function_returning_void()" without changing  
the meaning of the surrounding code.  Look at the following examples:

for (i = 0; i < 10; i++) {
	macro();
}

for (i = 0; i < 10; i++)
	if (i > 5)
		macro1();
	else
		macro2();

Cheers,
Kyle Moffett