Re: 'fd' file descriptor help

[Chris Wright]

* Nav Mundi ([e-mail]) wrote:
> Does anyone know what the file descriptor 'fd' pointer does?  My module makes 
> a system call [sys_open] to the kernal which then returns a fd value but I 
> don't know what this value means or how it gets it.  Does the fd value 
> signify a specific device or is it random?  Any ideas?

fd is a handle for the kernel file struct representing the file you
opened.  read include/linux/file.h::fd_install() to understand where
it's put, and include/linux/file.h::fcheck() as an example of retrieving
kernel object from the handle.

cheers,
-chris