Father & children Post: 97461

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Top Forums Programming Father & children Post 97461 by Jariya on Monday 30th of January 2006 05:58:07 PM

01-30-2006

Registered User

I do a pipe and then another pipe because im creating a pipe, referred with "tubo2",for father process and another one in each iteratino for each child.

the program compile ok. but there is an execution error: "broken pipe". also i realize that father doesnt execute this code:

Code:

...
if (pid)
{
       /* father */
       printf("\nhello..."); /* this line is only an example. 
                                      the program executes it. Everything ok..*/
       for(i=0; i<2; i++)  /* it doest go into this loop. why?! */
       {
                /* modification of "frase" */
                ...
        }
}
else
{
         read(...); /* the function returns -1. Error */
         ...
}

Perderabo:
I didnt paste it well; yes, semicolon is needed. And im going to review rules again!

Mmm, sorry i dont have a high level as you can see... but why did you say that the other writes and reads are all zero?

Last edited by Jariya; 01-30-2006 at 07:10 PM..

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usb_poison_urb

USB_POISON_URB(9)						   USB Core APIs						 USB_POISON_URB(9)

NAME

       usb_poison_urb - reliably kill a transfer and prevent further use of an URB

SYNOPSIS

       void usb_poison_urb(struct urb * urb);

ARGUMENTS

       urb
	   pointer to URB describing a previously submitted request, may be NULL

DESCRIPTION

       This routine cancels an in-progress request. It is guaranteed that upon return all completion handlers will have finished and the URB will
       be totally idle and cannot be reused. These features make this an ideal way to stop I/O in a disconnect callback. If the request has not
       already finished or been unlinked the completion handler will see urb->status == -ENOENT.

       After and while the routine runs, attempts to resubmit the URB will fail with error -EPERM. Thus even if the URB's completion handler
       always tries to resubmit, it will not succeed and the URB will become idle.

       The URB must not be deallocated while this routine is running. In particular, when a driver calls this routine, it must insure that the
       completion handler cannot deallocate the URB.

       This routine may not be used in an interrupt context (such as a bottom half or a completion handler), or when holding a spinlock, or in
       other situations where the caller can't schedule.

       This routine should not be called by a driver after its disconnect method has returned.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014							 USB_POISON_URB(9)