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 descrip-
 tor 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 program: 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