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From: Christian_Kaiser@f7220.n241.z2.fidonet.org (Christian Kaiser)
Newsgroups: comp.windows.ms.programmer
Subject: Help! Calling Fopen() In Dll
Message-ID: <1502352682@f7220.n241.z2.fidonet.org>
Date: 19 May 91 11:11:00 GMT
References: <6358@p1.f6.n242.z2.fidonet.org>
Reply-To: Christian_Kaiser%f7220.n241.z2@hippo.dfv.rwth-aachen.de (Christian Kaiser)
Organization: Maybe I should start labeling my software?
Lines: 36
Comment-To: Dxg@f1.n6000.z2.fidonet.org (Dxg)


 > First some info: I am using MS-C 6.0a and MS-C 3.0a.

No: I assume you use MS-Win 3.0a. MSC 3.0 would be too old...

 > I am calling a function from a .exe that is in a DLL.  This
 > function does an fopen() and then returns a FILE *.

OOOOOOOOOps. As far as I see, you made a lot of questionable things...

First of all, the FILE * in the my_fopen() is on the stack, so it will be 
overwritten when you use the stack next time (calling fprintf), and that will 
cause BIG trouble. So make the FILE * a static variable.

Second, you should declare all pointer parameters in combination with DLLs as 
FAR. So it should be

FILE FAR *my_fopen(LPSTR psFileName, LPSTR psMode)

that'll avoid the rest of your problems...

 > Am I doing something wrong or is impossible to call fopen() from within
 > a DLL and return the FILE * to the exe?

Of course you can. Just remember:

- declare pointers as far (remember 'CS != SS') and

- variables as static if they are used outside the function where they are 
declared (the FILE * in this case)

Ok?

Bye!
    Christian