Re: Simple question about comedi_fileno..

From: Patrick H. E. Foubet <foubet_at_seriane.fr> · Date: Fri, 15 Nov 2002 09:50:47 +0000

Hi Daniel,

Daniel Koch wrote:

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> Hi,
> 
> I've got a simple question trying to understand the cmd.c code. I'm not very 
> experienced in C programs yet, but I want to learn how cmd.c works. One line
> i don`t understand is
> 
> ret=read(comedi_fileno(dev),buf,BUFSZ);
> 
> I checked the comedilib reference but I couldn`t find comedi_fileno , buf and 
> BUFSZ. Can someone explain that to me ?
> 
> Sorry about asking this simple question..
> 

comedi_fileno(dev) is the transformation of dev getting by 
comedi_open(), to standard file id because read is a standard function
buf is a char * pointer
BUFSZ is the size of your buffer buf
for example you define
char buf[3000];
you must tell to read that you don't want get more than 3000 bytes.

and ret is the number of bytes you have got in buf after read.

HTH.

Patrick

> Daniel
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> 
> Daniel Koch (danielkoch_at_gmx.net)
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