[Zlib-devel] Fwd: zlib app crashes on release, not debug in Visual C++

[John Bowler]

> From: Tilman Hausherr <tilman at snafu.de>
> I've built a mini console application with Visual C++ 6 that uses the 
> zlib1.dll (1.2.5) http://zlib.net/zlib125-dll.zip that does nothing 
> except calling zlibVersion(). It crashes in release mode with an 
> access violation, but not in debug mode. I can run it in release mode 
> if I enable the /debug linker flag.

I can confirm that I get the same behavior with Visual Studio 2010 (Pro).
Maybe this explains one of the problems I had with libpng, I was becoming
more and more suspicious that mixing runtime DLLs might not work.  It seems
that there is a CRT specific entry point in the MicroSoft CRTs that must be
called after the DLL is loaded.

I'll try more debugging - the test program is attached (it works fine in
debug, but exits with 'Unhandled exception at 0x00905a4d in zlibtest.exe:
0xC0000005: Access violation.' in the release version.)

John Bowler <jbowler at acm.org>

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