opendarwin man page for pipe

PIPE(2) 						      BSD System Calls Manual							   PIPE(2)

NAME
     pipe -- create descriptor pair for interprocess communication

SYNOPSIS
     #include <unistd.h>

     int
     pipe(int *fildes);

DESCRIPTION
     The pipe() function creates a pipe, which is an object allowing unidirectional data flow, and allocates a pair of file descriptors.  The
     first descriptor connects to the read end of the pipe, and the second connects to the write end, so that data written to fildes[1] appears on
     (i.e., can be read from) fildes[0].  This allows the output of one program to be sent to another program: the source's standard output is set
     up to be the write end of the pipe, and the sink's standard input is set up to be the read end of the pipe.  The pipe itself persists until
     all its associated descriptors are closed.

     A pipe whose read or write end has been closed is considered widowed.  Writing on such a pipe causes the writing process to receive a SIGPIPE
     signal.  Widowing a pipe is the only way to deliver end-of-file to a reader: after the reader consumes any buffered data, reading a widowed
     pipe returns a zero count.

RETURN VALUES
     On successful creation of the pipe, zero is returned. Otherwise, a value of -1 is returned and the variable errno set to indicate the error.

ERRORS
     The pipe() call will fail if:

     [EMFILE]		Too many descriptors are active.

     [ENFILE]		The system file table is full.

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

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

HISTORY
     A pipe() function call appeared in Version 6 AT&T UNIX.

4th Berkeley Distribution					   June 4, 1993 					 4th Berkeley Distribution