PIPE(2)                  DOMAIN/IX SYS5                   PIPE(2)



NAME
     pipe - create an interprocess communication channel

USAGE
     pipe(fildes)
     int fildes[2];


DESCRIPTION
     The pipe system call creates an I/O mechanism called a pipe.
     The file descriptors returned can be used in read(2) and
     write(2) operations.  When the pipe is written using the
     descriptor fildes[1], up to 5120 bytes of data are buffered
     before the writing process is suspended.  A read(2) using
     the descriptor fildes[0] will pick up the data.

     It is assumed that after the pipe has been set up, two or
     more cooperating processes (created by subsequent fork(2)
     calls) will pass data through the pipe with read and write
     calls.

     The shell has a syntax that allows users to set up a linear
     array of processes connected by pipes.

     Read calls on an empty pipe (one with no buffered data and
     no writers) return an end-of-file.

     Attempts to write to a pipe that has no readers will gen-
     erate a SIGPIPE signal.

NOTES
     Deadlock will occur if more than 5120 bytes are necessary in
     any pipe among a loop of processes.

RETURN VALUE
     A successful call returns zero.  A failed call returns -1
     and sets errno as indicated below.

ERRORS
     The pipe call will fail if:

     [EMFILE]  Too many descriptors are active.

     [EFAULT]  The fildes buffer is in an invalid area of the
               process's address space.

RELATED INFORMATION
     sh(1), read(2), write(2), fork(2)





Printed 12/4/86                                            PIPE-1