PIPE(2V)                  SYSTEM CALLS                   PIPE(2V)



NAME
     pipe - create an interprocess communication channel

SYNOPSIS
     int pipe(fd)
     int fd[2];

DESCRIPTION
     The pipe() system call creates an I/O mechanism called a pipe
     and returns two file descriptors, fd[0] and fd[1].  fd[0] is
     opened for reading and fd[1] is opened for writing.  When the
     pipe is written using the descriptor fd[1] up to {PIPE_BUF} (see
     sysconf(2V)) bytes of data are buffered before the writing
     process is blocked.  A read only file descriptor fd[0] accesses
     the data written to fd[1] on a FIFO (first-in-first-out) basis.

     The standard programming model is that after  the  pipe  has
     been set up, two (or more) cooperating processes (created by
     subsequent fork(2V) calls) will pass data through  the  pipe
     using read(2V) and write(2V).

     Read calls on an empty pipe (no buffered data) with only one
     end  (all write file descriptors closed) return an EOF (end
     of file).

     A SIGPIPE signal is generated if a write on a pipe with only
     one end is attempted.

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

RETURN VALUES
     pipe() returns:

     0    on success.

     -1   on failure and sets errno to indicate the error.

ERRORS
     EFAULT         The array fd is in an  invalid  area  of  the
                    process's address space.

     EMFILE         Too many descriptors are active.

     ENFILE         The system file table is full.





Sun Release 4.1   Last change: 21 January 1990                  1






PIPE(2V)                  SYSTEM CALLS                   PIPE(2V)



SEE ALSO
     sh(1), fork(2V), read(2V), socketpair(2), write(2V)

BUGS
     Should more than {PIPE_BUF} bytes be necessary in  any  pipe
     among a loop of processes, deadlock will occur.