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Re: printf before main?

From: Ryan Arnold <ryan dot arnold at gmail dot com>
To: Brendan Miller <catphive at catphive dot net>
Cc: libc-help at sourceware dot org
Date: Tue, 23 Mar 2010 15:49:54 -0500
Subject: Re: printf before main?
References: <ef38762f1003231320i6bcbb54an25c94abc43bf0fe@mail.gmail.com>

On Tue, Mar 23, 2010 at 3:20 PM, Brendan Miller <catphive@catphive.net> wrote:
> Is it safe to call printf family functions, or other streams
> functionality before main? In other words, in global C++ constructors,
> or functions with __attribute__((constructor))?
>
> I'm wondering if any buffers for standard output are being allocated
> during that phase... I need to do some output potentially before main
> for logging purposes, and I'm wondering if I'd better off calling
> write directly.
>
> Brendan
>

Printf is _very_ heavyweight.  You should call write directly since
you probably don't need all of the formatting options provided by
printf.

Ryan S. Arnold

References:
- printf before main?
  - From: Brendan Miller

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