question abt select() on FC 3
 

Hi
I m having problem with the select call in my program.
IF i pass it FD_SETSIZE as first argument select (FD_SETSIZE, &readfs, NULL, NULL, NULL)it works fine but if i change it to something like
int fds= 4;
select (FD_SETSIZE, &readfs, NULL, NULL, NULL);
it never returns.
there is no error or anything.

btw i m using Linux FC 3
with gcc
gcc version 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)

any idea?

select (FD_SETSIZE, &readfs, NULL, NULL, NULL) with this argument set you are passing NULL as the last argument which is a timeout. And if you set this to NULL the select call will block just like a recv or accept call. If this is not what you want and you want select to return after a timeout then you will too create a timeval struct for the last argument with a timeout before each call to select (since select sets it to zero when it returns).

my question was i about first argument FD_SETSIZE.
if i keep it to FD_SETSIZE my program would work OK
but if i change it to something like 2 or some userdefined value it never comes back frm select()
(in both cases the last argument is NULL)

So you are saying if you call select in the following way.
int fds= 4;
select (fds, &readfs, NULL, NULL, NULL);

It will never return. How many FDs have you put into readfs?