Re: [bug-grep] search.c clean-up

[Elliott Hughes]

On Nov 23, 2004, at 00:53, Jim Meyering wrote:
> > and it seems to call strlen()
> > on constant strings even more times than it did before, which is only 
> > a small
> > and constant cost but not very tasteful.
>
> It is better practice to use strlen in such macros,
> in case the caller passes non-literal strings.
> I think of it as defensive programming.  More about this, below.
> The compiler we typically care about (gcc) can optimize away
> calls to strlen with a literal argument.

even if it can't optimize it out, this code is only executed once per 
invocation of grep. since the only way sizeof could be a valid 
alternative is if the strings are known at compile-time, we're 
guaranteed not to have a particularly large string to scan.

strlen's added safety at no cost sounds good to me.

i like this partial factorization -- even though there's more stuff to 
also come out -- because it's a meaningful chunk of functionality in 
its own right, and deserves a name.

i'd rather see a function than a multi-line macro, though.

--
http://www.jessies.org/~enh/