03-25-2004
I gave it some thought, and based on your reply I would like to do the following: "the parent could create a pipe with each of them and send a signal whenever you've just sent a command down the pipe"
-- I have to guarantee that when I send the command down the pipe and then the signal, this is all done atomically, I would also like to use semaphores to guard this section of the code, I do not want to travel the disabling interrupts route or busy waiting.
If this possible can someone point me to some sample code or resources for all tasks, creation of pipes and writing commands to it, signaling the process and using semaphores.
Thank you.
FI
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pipe(2) System Calls Manual pipe(2)
NAME
pipe() - create an interprocess channel
SYNOPSIS
DESCRIPTION
creates an I/O mechanism called a pipe and returns two file descriptors, fildes[0] and fildes[1]. fildes[0] is opened for reading and
fildes[1] is opened for writing.
A read-only file descriptor fildes[0] accesses the data written to fildes[1] on a first-in-first-out (FIFO) basis. For details of the I/O
behavior of pipes see read(2) and write(2).
By default, HP-UX pipes are not STREAMS-based. It is possible to generate the kernel so that all pipes created on a system are STREAMS-
based. This can only be done for HP-UX releases 10.0 and later. STREAMS-based FIFOs (created by or are not supported on HP-UX.
To generate a kernel that supports STREAMS-based pipes:
o STREAMS/UX must be installed.
o The module and the driver must be included in the file. (When STREAMS/UX is installed, and are automatically added to the system
file.)
o The tunable parameter (see streampipes(5)) must be set to 1 in the file. (This is not automatically done when STREAMS/UX is
installed.)
o The kernel must be generated and the system rebooted. Once this is done, all pipes created by will be STREAMS-based.
For more information, see
EXAMPLES
The following example uses to implement the command string
RETURN VALUE
returns one of the following values:
Successful completion.
Failure.
is set to indicate the error.
ERRORS
sets to one of the following error values if the corresponding condition is true.
or more file descriptors are currently open.
The system file table is full.
The file system lacks sufficient space to create the pipe.
Could not allocate resources for both Stream heads
(STREAMS-based pipes only).
SEE ALSO
sh(1), read(2), write(2), popen(3S), privileges(5), streampipes(5), streamio(7).
STANDARDS CONFORMANCE
pipe(2)