From:	Mat Hostetter <iclone!mjhostet AT cs DOT unm DOT edu>
Date:	Tue, 15 Jun 93 16:21:03 -0600
To:	djgpp AT sun DOT soe DOT clarkson DOT edu
Subject:	itimer stuff

I've nearly finished a package that gives djgpp users an interval  
timer, useful for Unix types like me porting SIGALRM code.  You  
specify a C function and a number of microseconds, and that function  
is called at approximately the given time.  My stuff is based on the  
1024 times/second real time clock interrupt (int 70h), and involves  
minor modifications to go32.exe.

It basically works, but there is one mysterious problem remaining.   
Under go32, the delays are taking 12 times as long as they should.   
It's as if something is eating 11/12 of the int 70 interrupts, or  
there is massive overhead somewhere.  I wrote similar code in Borland  
C (much, much easier) and the timing is exactly right.

I'll keep looking for the problem, but does this ring any bells?  As  
I've said before, I don't know much about DOS.

Once this works, I'll release it to the public domain.

-Mat

- Raw text -