Re: freopen and fopen not thread safe?

From:
Ulrich Eckhardt <eckhardt@satorlaser.com>
Newsgroups:
microsoft.public.vc.language
Date:
Wed, 03 Jun 2009 08:43:57 +0200
Message-ID:
<dmihf6-479.ln1@satorlaser.homedns.org>
Patrick Childers wrote:

I'm getting a crash in printf saying the stdout pointer is invalid. I
think that freopen and fopen are not thread safe when used with one of the
three pre-defined streams (stdin, stdout, stderr).

I posted a feedback to Microsoft at


https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=449513

I'm confused with their answer of "This issue is by design. It's not that
the functions are not thread safe. The problem is that you're bypassing
the CRT initialization using WinMain. "


Every executable has an entry point. Typically, that entry point is neither
main() nor WinMain(), but some internal function provided by the vendor
which eventually calls one of those. Now, if you create a console
application, the entry point is mainACRTStartup(), which initialises the
CRT ("C RunTime [library]"), part of which is the stdout. Since you are not
using that, CRT init is not performed and you can't use stdout.

Uli

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