Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c++ > #14534

Troubles when processes try to access to a char device

Show all headers | View raw

Hi,
I'm building a multi process application under Linux.

In the main process I initialize a char device and put is file 
descriptor in a variable dev_fd in the shared memory area.

## Main Process ##
...
dev_fd = open("/dev/mydev",O_RDWR))
...

In the other processes I want to use the device in this way:

## Other Processes ##
...
read(dev_fd, buffer);
...
write(dev_fd, buffer);
...

but "read" function always returns 255, while "write" function doesn't 
write the device :(

Where is the problem?

Thanks,
-- 
*Willy* - *Contatti*: http://snipurl.com/contatti
* *FAQ* di /it-alt.comp.software.mozilla/: http://www.FAQmozilla.org
* *Gratuiki* - Software Free: http://gratuiki.willygroup.org

Back to comp.lang.c++ | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

Troubles when processes try to access to a char device Willy <gruppi@willygroup.org> - 2012-02-27 08:58 +0100
  Re: Troubles when processes try to access to a char device gwowen <gwowen@gmail.com> - 2012-02-27 05:19 -0800
    Re: Troubles when processes try to access to a char device Willy <gruppi@willygroup.org> - 2012-02-27 14:41 +0100
      Re: Troubles when processes try to access to a char device gwowen <gwowen@gmail.com> - 2012-02-27 07:08 -0800
        Re: Troubles when processes try to access to a char device Willy <gruppi@willygroup.org> - 2012-02-27 16:42 +0100
          Re: Troubles when processes try to access to a char device gwowen <gwowen@gmail.com> - 2012-02-27 09:29 -0800
          Re: Troubles when processes try to access to a char device Dan Oxender <d?n.oxe????@gmail.com> - 2012-02-28 09:06 -0700
  Re: Troubles when processes try to access to a char device Alain Ketterlin <alain@dpt-info.u-strasbg.fr> - 2012-02-27 14:38 +0100

csiph-web