pipe(2)                          UNIX System V                          pipe(2)


NAME
      pipe - create an interprocess channel

SYNOPSIS
      #include <unistd.h>

      int pipe(int fildes[2]);

DESCRIPTION
      pipe 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 ONDELAY and ONONBLOCK flags are cleared.

      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.

      The FDCLOEXEC flag will be clear on both file descriptors.

      Upon successful completion pipe marks for update the statime, stctime,
      and stmtime fields of the pipe.

      pipe fails if:

      EMFILE         If {OPENMAX}-1 or more file descriptors are currently
                     open for this process.

      ENFILE         A file table entry could not be allocated.

SEE ALSO
      fcntl(2), getmsg(2), poll(2), putmsg(2), read(2), write(2), streamio(7).
      sh(1) in the User's Reference Manual.

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

NOTES
      Since a pipe is bi-directional, there are two separate flows of data.
      Therefore, the size (stsize) 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
      (stsize) 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).








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