🚀 go-pugleaf

myao@mailhost.ecn.uoknor.edu (Minghua Yao) writes:

>I have a C module which uses "fopen()" to open a file. When called by a 
>C main(), the module works well and the file can be opened. 
>But if this module is called by a TSR code (which is loaded at an interrupt 
>not used by the DOS, and is executed by activating this interrupt), 
>the file which does exist cannot be opened often times. Sometimes 
>(seldom,though) the file can be opened. If so, the machine will die. 
>The behavior seems to be undefinte.

>The working enviroment is DOS. I use 80x86 assembly for The TSR and 
>Borland C for the C module. The C module is resident part of the TSR.

>Anybody's help will be greatly appreciated.

High,

there are possible two reasons. 
1. InDOS-Flag
   Indeed it is important that there is no other action in DOS, because
   DOS is not reentrant. The way to check it out is already discribed.

2. The stack !!
   The C-module fopen() uses a very large buffer for reading the file.
   And this buffer will be allocated on the normal stack. If perhaps you
   have the DOS-stack activ, it will be the reason. If you use a stack
   that you have defined, perhaps it will be too small.
   I also used the fopen()-module and have had the same results you have
   now.
   The InDOS-flag did not help. I have changed all the fopen-calls to the
   low-level-routine open(). With the open()-module it runs fine and I did
   not need a too large stack for the buffer.

Perhaps it helps

   Rainer


--
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Rainer Wenn     				       rainer@tpki.toppoint.de
24145 Kiel-Meimersdorf
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