From:	"Dahl" <no-spam-to:dahl AT c64 DOT org>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Detecting interrupt on printer port
Date:	Wed, 12 Aug 1998 22:51:49 +0200
Organization:	Algonet/Tninet
Lines:	27
Message-ID:	<6qsv6g$4ip$1@cubacola.tninet.se>
References:	<C22A1.62$Qi3 DOT 325552 AT sapphire DOT mtt DOT net> <35D0BF71 DOT 9FB3EE0B AT unb DOT ca> <625A1.98$Qi3 DOT 473241 AT sapphire DOT mtt DOT net>
NNTP-Posting-Host:	du212-150.ppp.algonet.se
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Michel Gallant skrev i meddelandet <625A1.98$Qi3 DOT 473241 AT sapphire DOT mtt DOT net>...
>
>Endlisnis wrote in message <35D0BF71 DOT 9FB3EE0B AT unb DOT ca>...
>>Michel Gallant wrote:
>>
>>
>>use:
>>volatile int counter = 0;

All registers and addresses concerning the parallel-port should be treated
as volatile addresses.

That should do it

>>
>>You need to do this because DJGPP will likely move counter into a
>register
>>during the loop where you print the value in printf.  Setting a
>variable to
>>'volatile' forces DJGPP to reload 'counter' from memory every time it
>is
>>used.
>>

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