NAME

pipe − create an interprocess channel

SYNOPSIS

int pipe (fildes)
int fildes[2];

DESCRIPTION

Pipe creates an I/O mechanism called a pipe and returns two file descriptors, fildes[0] and fildes[1]. Fildes[0] is opened for reading and fildes[1] is opened for writing.

Writes up to 5120 bytes of data are buffered by the pipe before the writing process is blocked.  A read on file descriptor fildes[0] accesses the data written to fildes[1] on a first-in-first-out basis.

No process may have more than 20 file descriptors open simultaneously. 

Pipe will fail if 19 or more file descriptors are currently open.  ­[EMFILE]

RETURN VALUE

Upon successful completion, a value of 0 is returned.  Otherwise, a value of −1 is returned and errno is set to indicate the error. 

SEE ALSO

sh(1), read(2), write(2). 

ASSEMBLER

moveq#42,D0
movlfildes,A0
trap#0

Carry bit set on failure and cleared on success. 

Read file descriptor in D0.  Write file descriptor in D1. 

Version 2.4  —  May 08, 1986