man.postnix Miscellaneous man pages of Plan 9 related material

     SYS-PIPE(2)                                           SYS-PIPE(2)

     NAME
          pipe - create an interprocess channel

     SYNOPSIS
          include "sys.m";
          sys := load Sys Sys->PATH;

          pipe: fn(fds: array of ref FD): int;

     DESCRIPTION
          Pipe creates a buffered channel for interprocess I/O via
          file descriptors.  It allocates a pipe from the pipe device
          and returns in the array fds file descriptors for the two
          pipe ends. Both returned file descriptors are opened for
          both reading and writing (Sys->ORDWR).  Data written on one
          file descriptor can be read from the other.  The details of
          flow control and buffering are given in pipe(3). When no
          references remain to the file descriptor representing one
          end of a pipe, and all remaining data has been read at the
          other end, subsequent reads at that end will return 0 bytes.
          Writes to a pipe with no reader produce an exception.

          The array fds passed to the system call must have a length
          of at least 2; only entries 0 and 1 are updated.

          Limbo applications typically use typed Limbo channels, not
          pipes, for efficient communication by cooperating processes.
          Pipes are still useful, however, to connect applications
          that do not (or cannot) share such channels, or when a sys-
          tem interface requires a file descriptor.  For instance, a
          process that serves the 9P protocol can pass the file
          descriptor for one end of a pipe to Sys->mount (see sys-
          bind(2)), and read and write 9P messages on the other end of
          the pipe.

     DIAGNOSTICS
          Returns 0 on success; -1 on failure.

     SEE ALSO
          pipe(3)

     Page 1                       Plan 9             (printed 4/19/24)