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From: Oliver <oliver DOT schoenborn AT utoronto DOT ca>
Subject: Re: questions about DLL's: .a, .def, and .dll
Date: Fri, 27 Aug 2004 19:39:41 +0000 (UTC)
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References: <loom DOT 20040827T173827-426 AT post DOT gmane DOT org> <Pine DOT GSO DOT 4 DOT 61 DOT 0408271423560 DOT 6181 AT slinky DOT cs DOT nyu DOT edu>
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Igor Pechtchanski <pechtcha <at> cs.nyu.edu> writes:

> On Fri, 27 Aug 2004, Oliver wrote:
> 
> > creating a .a file, a .def file, and a .dll file, yet I can
> > build a program that links to, e.g., mylib.dll, with only "-L. -lmylib",
> > *wihtout* having the .def or .a available. So where and when are the .a and
> > .def files needed?
> 
> The newer versions of gcc apparently allow you to link directly to a .dll
> file.  The .def and .a are needed for older versions of gcc, and possibly
> for some other tools.

I guess the .def file might be used if you created your dll in cygwin/mingw but 
are creating your program with VC++ and linking to your non-VC++ dll. (?)

> ...a DLL built with C++ symbols won't be usable from
> other applications that try to call those functions.  The reason you want
> it for DllMain is that the Windows loader will be looking for the unmunged
> name "DllMain".  Are you sure that it's really invoked when the DLL is

Yes. I even tried it on the latest dllhelpers C++ example: just renamed 
dllinit.c to .cc and changed makeit.bat to use g++ instead of gcc, and 
everything still works. Perhaps g++ "knows" to leave DllMain alone? Or perhaps 
the APIENTRY macro that appears just in front of DllMain prevents munging? 

Oliver




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