How to access the nodes under the /dev directory to access the device?

Nishant Desai · 11-17-2006, 01:01 AM

Dear All,

I want to access the parallel port in my program and for that i want to access the node from the /dev directory, which relates the parallel port.

I know that to create the node, there is a command : "mknod nodename c majorno. minorno", but dont know how to access that node in my application, pls show me the way to do so.

Thanks in Advance,
Nishant

jtshaw · 11-17-2006, 06:49 PM

Pretend like it is a file and use it accordingly. Unix/Linux is a "everything is a file" OS. The same routines (open, close, read, write, lseek, ect.) are typically available for every device. Some drivers also support ioctl messages which can be issued with the ioctl system call.

See also:
man 2 open
man 2 close
man 2 read
man 2 write
man 2 lseek
man 2 ioctl

firstfire · 11-18-2006, 04:09 PM

Take a look at

http://www.faqs.org/docs/Linux-mini/...ogramming.html

especially sections 2 and 9 (Example).