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Date: Wed, 1 Aug 2007 14:39:26 -0400
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
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Subject: Re: is LD_PRELOAD available in cygwin?
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On Wed, Aug 01, 2007 at 08:23:15AM -0700, Brian Dessent wrote:
>G?nther Jedenastik wrote:
>
>> using g++ to compile a dll which overload's the open(); glibc system call.
>> Using preload i want to load my own dll with my open(); function. using 
>> dlsym(); i try to load the glibc open(); function.
>
>Cygwin does not use glibc.  glibc is Linux-specifc.
>
>> Q1: is LD_PRELOAD available in cygwin? if yes, any hint's why it's not
>> working? (maybe some configuration problem or so, any hint would be
>> helpfull)
>> Q2: are there any alternative ways to preloading causing the same result?
>
>No, LD_PRELOAD is an aspect of ELF dynamic loaders and is not available
>on Windows.  It's not something that Cygwin can provide since it is a
>function provided by the program loader, i.e. the operating system.

Sorry, Brian, but this isn't correct.  LD_PRELOAD has been available for
Cygwin for a while.

It's not 100% like linux but it is close.  You can only override cygwin
functions with it but that should work for open().  If this isn't working
under cygwin, I'd suspect function decorations are not right, i.e., the
open() function name being trapped doesn't look the same as the open in
cygwin1.dll.

...either that or LD_PRELOAD is broken.  I haven't played with it for a
while.

cgf

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