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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: Is there any place to talk about language features?
Date: Wed, 05 Oct 2016 12:18:29 -0700
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Thiago Adams <thiago.adams@gmail.com> writes:
> On Wednesday, October 5, 2016 at 2:38:55 PM UTC-3, 
> ...
>> The design of "printf" trades off run-time complexity and code size for
>> compiler simplicity. 
>
> Some thoughts..
>
> Compilers can check in compile time the printf arguments. (Visual
> Studio 2015 for instance does)

Only if the format string is, or can be resolved to, a string literal --
which is the most common case, so it's a worthwhile check.

> So, I was wondering that some compiler could possible generate inline
> and static code for printf.
> printf("%d", 1); //compiler says: ok is "1"
> printf("%d", i); //compiler says: ok is just itoa

Yes, gcc does this.  For example, it's able to compile
    printf("%s\n", "hello");
as a call to puts().

It doesn't do the same for
    printf("%d\n", 42);
probably (this is speculation) because constant arguments to "%d" are
not as common.  There's certainly no fundamental reason it couldn't
compile that to the equivalent of `puts("42")`.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"