From: Ian Lance Taylor <iant@google.com>
To: Reza Roboubi <reza@parvan.net>
Cc: gcc-help@gcc.gnu.org
Subject: Re: how is strcmp implemented so efficiently?
Date: Wed, 01 Oct 2008 00:58:00 -0000 [thread overview]
Message-ID: <m3od255dzv.fsf@google.com> (raw)
In-Reply-To: <48E2AAD2.4030504@parvan.net> (Reza Roboubi's message of "Tue\, 30 Sep 2008 15\:40\:18 -0700")
Reza Roboubi <reza@parvan.net> writes:
> I noticed that strcmp is extremely smart. It knows when one parameter
> has constant length, determined at compile time. In that case it
> reverts to an inline version of the x86 string commands.
>
> I looked into the headers and strcmp is defined as an extern(not inline.)
>
> How would I ever write such an efficient function? Is it
> possible(even _with_ the use of asm?!)
The compiler automatically recognizes strcmp when compiling C/C++
code, among many other builtin functions. See the docs for the
complete list.
Ian
prev parent reply other threads:[~2008-10-01 0:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-30 22:40 Reza Roboubi
2008-09-30 22:55 ` me22
2008-10-01 0:58 ` Ian Lance Taylor [this message]
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