pipe - create pipe

Syntax	#include <unistd.h> int pipe(int fildes[2]);
Description	pipe() creates a pipe and places two file descriptors, which refer to the open file descriptions for the read and write ends of the pipe, into the arguments fildes[0] and fildes[1]. These integer values are the two lowest available at the time of the pipe() call. The O_NONBLOCK bit is not set for either of the two file descriptors (the fcntl() function can be used to set the O_NONBLOCK bit). Data can then be written to the file descriptor fildes[1] and read from file descriptor fildes[0]. A read on the file descriptor fildes[0] accesses the data written to file descriptor fildes[1] on a first-in-first-out basis. A process has the pipe open for reading if it has a file descriptor open that refers to the read end of the pipe, i.e. fildes[0]; the same applies to writing and the write end, i.e. fildes[1]. Upon successful completion, pipe() will mark the stat structure components of the pipe, i.e. st_atime, st_ctime and st_mtime, for update. The FD_CLOEXEC bit is not set for either of the two file descriptors.
Return val.	0	if successful.
	-1	if an error occurs. errno is set to indicate the error.
Errors	pipe() will fail if:
	EMFILE	{OPEN_MAX} minus 2 file descriptors are already open for this process.
	ENFILE	The number of simultaneously open files in the system would exceed a system-imposed limit.
Notes	pipe() is executed only for POSIX files.
See also	fcntl(), read(), write(), unistd.h.