Fw: select(2)

Fw: select(2)

[Brad Bonkoski]

----- Original Message -----
From: "Brad Bonkoski" <bbonkoski@xyterra.com>
To: <redhat-list@redhat.com>
Sent: Friday, August 03, 2001 10:15 AM
Subject: select(2)


> Hello,
>
> this code:
> fd_set set;
> struct timeval timeout;
> int len_inet;
> int n;
> FD_ZERO(&set);
> timeout.tv_sec = 1L;
> FD_SET(sc_sock,&set);
> n = select(sc_sock+1, &set, NULL, NULL, &timeout);
> if (n == -1)
>

>   perror("select()\n");
>   exit(1);
> }
>
> Works just fine on one machine, i.e. select() does not return a '-1' which
lets it run through the rest of the code.  However, on other machines, it
does not work fine, -1 is always returned by select() with error of: Invalid
arguement
>
> Any ideas on where I could look to fix this problem?  Something in the
syntax of the posted code, or should I be looking at the creation of the
socket?
> TIA.
> Brad
>
>
>
>
>

Re: Fw: select(2)

[Matti Aarnio]

On Fri, Aug 03, 2001 at 01:34:34PM -0700, Brad Bonkoski wrote:
> > Hello,
> >
> > this code:
> > fd_set set;
> > struct timeval timeout;
> > int len_inet;
> > int n;
> > FD_ZERO(&set);
> > timeout.tv_sec = 1L;

  I would venture a guess that as you don't EXPLICITELY
  initialize the   timeout.tv_usec  value to be
  within  0  to   999999   it may get some system dependent
  sometimes random, sometimes fixed value (the joys of these
  stack-allocated "automatic" variables..)

  For short:  Smells of UNINITIALIZED PARAMETER DATA.

> > FD_SET(sc_sock,&set);
> > n = select(sc_sock+1, &set, NULL, NULL, &timeout);
> > if (n == -1)
> >
> 
> >   perror("select()\n");
> >   exit(1);
> > }
> >
> > Works just fine on one machine, i.e. select() does not return a '-1' which
> lets it run through the rest of the code.  However, on other machines, it
> does not work fine, -1 is always returned by select() with error of: Invalid
> arguement
> >
> > Any ideas on where I could look to fix this problem?  Something in the
> syntax of the posted code, or should I be looking at the creation of the
> socket?
> > TIA.
> > Brad
> >
> >
> >
> >
> >
> 
> 
> 
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