The FAQ/User Manual leads everyone in completely the wrong direction.
If anyone else wants to get CYGWIN C++ programs running as dlls loaded by Visual C++ programs, use the attached example as a basis, it is *really* simple. This only allows Visual C++ to access the C functions of course, but that allows the generation of a simplified layer to gcc's c++ and our own c++ libraries. We are now able to interface our cygwin programs with our Maya plugin (which is forced unfortunately to use VC++). Regards --------------------------------- Q-Games, Dylan Cuthbert. http://www.q-games.com ----- Original Message ----- From: "Dylan Cuthbert" <[EMAIL PROTECTED]> To: "Larry Hall (RFK Partners, Inc)" <[EMAIL PROTECTED]>; "Cygwin@Cygwin. Com" <[EMAIL PROTECTED]> Sent: Thursday, February 14, 2002 12:06 PM Subject: Re: cygwin gcc DLLs loaded by Visual C++ crashing > Thanks for the reply. > > I have searched the mailing lists high and low and as far back as 1998 and > there are some references to this problem and some solutions, yet there are > no definitive "this works" type responses ( in fact, almost all the > responses I found seemed like temporary hacks ) and it would take a long > time to try implementing all the various solutions listed with no guarantee > they work. Maybe I'm searching with the wrong string - I'm looking under > subjects such as "initializing cygwin from dll" or "initialize cygwin dll", > am I missing some important keyword? > > The closest thing I have found is probably the "use LoadLibrary" to load the > cygwin.dll manually and then calling cygwin_dll_init(), but even that > crashes according to > http://sources.redhat.com/ml/cygwin/2001-08/msg00790.html (couldn't find > any response confirming or denying this mail) > > Then there's the (from 1998) use the "crt0.o" to link with and create a > dummy thread and a main() which doesn't exit - this seems like a complete > hack. I think this is probably the wrong direction, right? > > Then there's this comment from cgf - > http://sources.redhat.com/ml/cygwin/2000-12/msg00366.html which seems to say > that cygwin_dll_init() is the way to go. > > However, when I try using cygwin_dll_init I get an exception error, I > couldn't find any definition of a function called cygwin_dll_init in any > header file or library file anywhere so I force-ably extern'ed it. Does it > really exist, if so, where? > > Any ideas, anyone? > > --------------------------------- > Q-Games, Dylan Cuthbert. > http://www.q-games.com > ----- Original Message ----- > From: "Larry Hall (RFK Partners, Inc)" <[EMAIL PROTECTED]> > To: "Dylan Cuthbert" <[EMAIL PROTECTED]>; "Cygwin@Cygwin. Com" > <[EMAIL PROTECTED]> > Sent: Thursday, February 14, 2002 12:34 AM > Subject: Re: cygwin C++ DLLs and inter-operation with M$OFT > > > > At 05:58 AM 2/13/2002, Dylan Cuthbert wrote: > > >To anyone who can help, > > > > > >We've been having some fun creating DLLs that need to be loaded by some > > >Visual C++ code. The code in the dll itself, ie. the interface is C so > > >there aren't any name mangling problems. However, using v3.0.3 of GCC we > > >get unresolved symbol errors for any libstdc++ we do within the dll. > These > > >errors don't occur after using the -V 2.95.3-5 option to gcc to revert to > > >the originally packaged compiler - I had a good poke around but I > couldn't > > >work out why the symbols couldn't be resolved. > > > > > >Anyway, after reverting to 2.95.3-5, our test code compiles but when we > call > > >any cygwin dll code (from the VS application) we get an exception error > in > > >cygwin1.dll - if the code uses any stdlib type stuff (such as memory > > >allocation, printf etc). There is no C++ code in there at all now. > > > > > >I've read through the faqs and documentation and searched the mailing > list > > >but I can't find any fixes for this problem (although a couple of other > > >people do mention it). Is there just some obvious initialisation stuff > I'm > > >missing somewhere? > > > > > > Probably. This has been mentioned in the past. You want to look at the > > Cygwin initialization code to see what happens there. It needs to happen > > when the DLL is loaded by non-Cygwin apps as well. Some of this may come > > for free at this point. Discussion of this issue was quite some time ago > > (check the developer email archives if you're curious) and I don't > remember > > the final consensus and/or changes. But, the archives should have the > > history and the startup code should give you a hint of the current state. > > > > > > > > Larry Hall [EMAIL PROTECTED] > > RFK Partners, Inc. http://www.rfk.com > > 838 Washington Street (508) 893-9779 - RFK Office > > Holliston, MA 01746 (508) 893-9889 - FAX > > > > > -- > Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple > Bug reporting: http://cygwin.com/bugs.html > Documentation: http://cygwin.com/docs.html > FAQ: http://cygwin.com/faq/ >
testdll.zip
Description: Zip compressed data
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