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From: risto@tuura.UUCP (Risto Lankinen)
Newsgroups: comp.windows.ms.programmer
Subject: Re: Windows SDK and external functions
Message-ID: <971@tuura.UUCP>
Date: 28 Jan 91 10:08:17 GMT
References: <16458.27a0406a@ul.ie>
Organization: Nokia Data Systems Oy
Lines: 34

oreillyj@ul.ie writes:


>I am currently porting a large amount of 'C' code to the windows environment.
>Some of the code uses a plug-in sound card the functions for which are
>in an MS C library.  When I incorporate calls to  these functions in the
>windows code two things happen. Firstly the actual function doesn't work
>and secondly the system usually crashes.

Hi!

There are two possible reasons:  Either the library routines need to install
their own interrupt handler, which moves in memory (while it shouldn't do so)
when the other Windows applications allocate memory, or the library routines
depend on C start-up code, which is a bit different for the Windows programs
from the standard C programs.

If the library installs its own interrupt handler, you should declare the
segment containing it as FIXED, and probably prevent the same interrupt from
being re-vectored by the same program (either calling the routines only from
a DLL, which automatically is single-instance, or making your program check
the 'hPrevInst' before initializing the library).

It is also possible that the library inserts an auto-initialize vector in the
XIB -segment, which is part of the standard C start-up code.  In this case, 
the only way to prevent multiple initialization is to call library routines
from a DLL and nowhere else.

Terveisin: Risto Lankinen
-- 
Risto Lankinen / product specialist ***************************************
Nokia Data Systems, Technology Dept *  2                              2   *
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