SYS-PIPE(2)SYS-PIPE(2)NAME
pipe - create an interprocess channel
SYNOPSIS
include "sys.m";
sys := load Sys Sys->PATH;
pipe: fn(fds: array of ref FD): int;
DESCRIPTION
Pipe creates a buffered channel for interprocess I/O via file descrip‐
tors. It allocates a pipe from the pipe device and returns in the
array fds file descriptors for the two pipe ends. Both returned file
descriptors are opened for both reading and writing (Sys->ORDWR). Data
written on one file descriptor can be read from the other. The details
of flow control and buffering are given in pipe(3). When no references
remain to the file descriptor representing one end of a pipe, and all
remaining data has been read at the other end, subsequent reads at that
end will return 0 bytes. Writes to a pipe with no reader produce an
exception.
The array fds passed to the system call must have a length of at least
2; only entries 0 and 1 are updated.
Limbo applications typically use typed Limbo channels, not pipes, for
efficient communication by cooperating processes. Pipes are still use‐
ful, however, to connect applications that do not (or cannot) share
such channels, or when a system interface requires a file descriptor.
For instance, a process that serves the 9P protocol can pass the file
descriptor for one end of a pipe to Sys->mount (see sys-bind(2)), and
read and write 9P messages on the other end of the pipe.
DIAGNOSTICS
Returns 0 on success; -1 on failure.
SEE ALSOpipe(3)SYS-PIPE(2)
