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Hi

I'm porting a client writen in C++ to python. What is the way to get a
timeout in an select for one socket?
the c++ code is:


FD_ZERO(&fds);
FD_SET(fd_sock, &fds);
tv.tv_sec=2;
tv.tv_usec=0;
n = select(fd_sock+1,&fds,NULL,NULL,&tv);
sendto(...)

Thanks

Zunbeltz

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On Wed, Oct 22, 2003 at 11:15:35AM +0200, Zunbeltz Izaola wrote:
> Hi
>
> I'm porting a client writen in C++ to python. What is the way to get a
> timeout in an select for one socket?
> the c++ code is:
>
>
> FD_ZERO(&fds);
> FD_SET(fd_sock, &fds);
> tv.tv_sec=2;
> tv.tv_usec=0;
> n = select(fd_sock+1,&fds,NULL,NULL,&tv);
> sendto(...)

The python code is (assuming your socket.socket object is in a variable
called 'sock'):

import select
r, w, e = select.select([sock], [], [], 2)
if r:
sock.sendto(...)

-Andrew.

On Wed, Oct 22, 2003 at 10:02:00PM +1000, Andrew Bennetts wrote:
> On Wed, Oct 22, 2003 at 11:15:35AM +0200, Zunbeltz Izaola wrote:
> > Hi
> >
> > I'm porting a client writen in C++ to python. What is the way to get a
> > timeout in an select for one socket?
> > the c++ code is:
> >
> >
> > FD_ZERO(&fds);
> > FD_SET(fd_sock, &fds);
> > tv.tv_sec=2;
> > tv.tv_usec=0;
> > n = select(fd_sock+1,&fds,NULL,NULL,&tv);
> > sendto(...)
>
> The python code is (assuming your socket.socket object is in a variable
> called 'sock'):
>
> import select
> r, w, e = select.select([sock], [], [], 2)
> if r:
> sock.sendto(...)

Oh, I hurried too much and misread your code. You seem to want to always
call sendto, regardless of the result of the select call. In that case it's
even easier:

import select
select.select([sock], [], [], 2) # Just throw away the results
sock.sendto(...)

Anyway, hopefully it should be clear enough how to use select in python now


-Andrew.

Dnia 22 Oct 2003 11:15:35 +0200, Zunbeltz Izaola napisa³(a):

> I'm porting a client writen in C++ to python. What is the way to get a
> timeout in an select for one socket?

Quote from the ,,7.3 select -- Waiting for I/O completion'':

The optional timeout argument specifies a time-out as a floating point
number in seconds.

So, it'll be something like this:

n = select.select([fds], [], [], 2)[0][0]

--
[ Wojtek Walczak - gminick (at) underground.org.pl ]
[ <http://gminick.linuxsecurity.pl/> ]
[ "...rozmaite zwroty, matowe od patyny dawnosci." ]

Wojtek Walczak wrote:
>
> Dnia 22 Oct 2003 11:15:35 +0200, Zunbeltz Izaola napisa³(a):
>
> > I'm porting a client writen in C++ to python. What is the way to get a
> > timeout in an select for one socket?
>
> Quote from the ,,7.3 select -- Waiting for I/O completion'':
>
> The optional timeout argument specifies a time-out as a floating point
> number in seconds.
>
> So, it'll be something like this:
>
> n = select.select([fds], [], [], 2)[0][0]

At first glance, this appears unsafe. What if the fds socket
is not ready after the timeout?

You will, I think, get an IndexError raised.

-Peter