On 3/29/07, Rick Brown <[EMAIL PROTECTED]> wrote:
Hi,
Could some one please explain me the differences and similarities
between fcntl and ioctl?
Is one built upon the other?
No
AFAIK, both are used for handling of very
device specific commands by the driver.
not both,
this goes well with ioctl
as ioctl is customizable, there is an ioctl method in the
struct file_operations.
so a driver writer can define some device specific tasks
& hook her own method to execute them via an ioctl
http://lxr.linux.no/source/fs/ioctl.c#L159
fcntl is not customizable by a driver
there are some fixed task which it performs
like
setting the close on exec flag
duplicate fd
set/get owner
etc
have a look at
sys_fcntl
http://lxr.linux.no/source/fs/fcntl.c#L385
& its worker
do_fcntl
http://lxr.linux.no/source/fs/fcntl.c#L315
we can say that fcntl dosen't bother if its a regular file
or a device specific file
where as ioctl changes its color in these case
--
Milind Arun Choudhary
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