Re: 'fd' file descriptor help

Chris Wright (chris@wirex.com)
Thu, 6 Dec 2001 13:45:19 -0800


* Nav Mundi (nmundi@karthika.com) 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
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