pipe(2) [hpux man page]

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)

pipe(2) 							   System Calls 							   pipe(2)

NAME

       pipe - create an interprocess channel

SYNOPSIS

       #include <unistd.h>

       int pipe(int fildes[2]);

DESCRIPTION

       The  pipe() function creates an I/O mechanism called a pipe and returns two file descriptors, fildes[0] and fildes[1]. The files associated
       with fildes[0] and fildes[1] are streams and are both opened for reading and writing.  The O_NDELAY, O_NONBLOCK, and FD_CLOEXEC	flags  are
       cleared on both file descriptors. The fcntl(2) function can be used to set these flags.

       A  read	from  fildes[0] accesses the data written to fildes[1] on a first-in-first-out (FIFO) basis and a read from fildes[1] accesses the
       data written to fildes[0] also on a FIFO basis.

       Upon successful completion pipe() marks for update the st_atime, st_ctime, and st_mtime fields of the pipe.

RETURN VALUES

       Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The pipe() function will fail if:

       EMFILE	       More than {OPEN_MAX} file descriptors are already in use by this process.

       ENFILE	       The number of simultaneously open files in the system would exceed a system-imposed limit.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       sh(1), fcntl(2), fstat(2), getmsg(2), poll(2), putmsg(2), read(2), write(2), attributes(5), standards(5), streamio(7I)

NOTES

       Since a pipe is bi-directional, there are two separate flows of data. Therefore, the size (st_size) returned by a  call	to  fstat(2)  with
       argument   fildes[0]  or  fildes[1]  is the number of bytes available for reading from fildes[0] or fildes[1] respectively. Previously, the
       size (st_size) returned by a call to fstat() with argument fildes[1] (the write-end) was the number of bytes  available	for  reading  from
       fildes[0] (the read-end).

SunOS 5.10							    23 Apr 2002 							   pipe(2)