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

NAME

     pipe -- create descriptor pair for interprocess communication

SYNOPSIS

     #include <unistd.h>

     int
     pipe(int fildes[2]);

DESCRIPTION

     The pipe() function creates a pipe (an object that allows unidirectional data flow) and allocates a pair of file descriptors.  The first
     descriptor connects to the read end of the pipe; the second connects to the write end.

     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 pro-
     gram: the source's standard output is set up to be the write end of the pipe; the sink's standard input is set up to be the read end of the
     pipe.  The pipe itself persists until all of 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.

     The generation of the SIGPIPE signal can be suppressed using the F_SETNOSIGPIPE fcntl command.

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:

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

     [EMFILE]		Too many descriptors are active.

     [ENFILE]		The system file table is full.

SEE ALSO

     sh(1), fork(2), read(2), socketpair(2), fcntl(2), write(2)

HISTORY

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

4th Berkeley Distribution					 February 17, 2011					 4th Berkeley Distribution