Re: shortcut of ":" but not /bin/true

[David Boyce]

At 09:42 AM 5/18/2004, Noel Yap wrote:
> I was thinking more upon startup, but you're right, the performance hit 
> may not be worth it.  Maybe a lazier approach might work, though.  For 
> example, what if this test were done when it sees that it needs to know 
> whether the command is a built-in or not?  Of course, once the test is 
> done, it won't need to do it again for future executions of the command.

I completely agree that runtime testing is both too slow and too 
complicated. I know nothing about autotools/configure stuff but is it not 
possible for the ./configure script to determine whether the /bin/sh on 
that platform uses builtins? That might be worth looking into.

> Anyway, from what I understood of David's numbers, perl will build only 1% 
> faster.  Is it really worth the added complexity?

I didn't mention it before but the real issue - and the reason I noticed it 
in the first place - shows up when you start doing more advanced things 
with build scripts. E.g. when distributing builds to other systems there's 
a much higher fixed cost per script. Simply executing "/bin/true" or even 
"/bin/sh -c /bin/true" isn't such a big deal but when you start running the 
equivalent of "rsh <host> /bin/true" you begin to feel the pain.

But again, the pain is bearable and in my own toolset I can optimize it out 
in another layer anyway. I just thought the question of whether to inline 
"true" should be considered ("false" is less important as it's unlikely to 
be run more than once in a build).

-David