for a socket file , what does "file->f_op->poll()" do ?

for a socket file , what does "file->f_op->poll()" do ?

[horseriver]

hi:

  for a socket file point , what will this function do ?

  file->f_op->poll();       ///poll is declared  in the file-operations struct .

  but I do not find this function's definition .

  Is there some advice?

thanks!

for a socket file , what does "file->f_op->poll()" do ?

[Henrique Rodrigues]

In the file_operations struct, it is a pointer to another function that
your module/code should implement. The file_operations struct, like many
others in the kernel, contains a generic set of functions that the kernel
expect your code will implement.

In the proc fs for example, mounts_poll (
http://lxr.linux.no/linux+v2.6.38.8/fs/proc/base.c#L639) is an
implementation of the poll function that is later associated with the
pointer of the file_operations structure at
http://lxr.linux.no/linux+v2.6.38.8/fs/proc/base.c#L661

Take a look at the LDD (http://lwn.net/Kernel/LDD3/) to learn how a driver
implementation should use these kind  of functions to understand it better.

-- 
Henrique Rodrigues
http://www.dcc.ufmg.br/~hsr

On Fri, Jan 11, 2013 at 12:14 AM, horseriver <horserivers@gmail.com> wrote:

> hi:
>
>   for a socket file point , what will this function do ?
>
>   file->f_op->poll();       ///poll is declared  in the file-operations
> struct .
>
>   but I do not find this function's definition .
>
>   Is there some advice?
>
> thanks!
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
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