pipe(3) [plan9 man page]

PIPE(3) 						     Library Functions Manual							   PIPE(3)

NAME

       pipe - two-way interprocess communication

SYNOPSIS

       bind #| dir

       dir/data
       dir/ctl
       dir/data1
       dir/ctl1

DESCRIPTION

       An  attach(5) of this device allocates two new streams joined at the device end.  X/data and x/ctl are the data and control channels of one
       stream and x/data1 and x/ctl1 are the data and control channels of the other stream.

       Data written to one channel becomes available for reading at the other.	Write boundaries are preserved: each read terminates when the read
       buffer is full or after reading the last byte of a write, whichever comes first.

       Written data is buffered in kernel stream blocks.  The writer will block once the stream is full, typically after 32768 bytes or 16 writes.
       The writer will resume once the stream is less than half full.

       If there are multiple writers, each write is guaranteed to be available in a contiguous piece at the other end of the pipe.  If	there  are
       multiple readers, each read will return data from only one write.

       The  pipe(2)  system call performs an attach of this device and returns file descriptors to the new pipe's data and data1 files.  The files
       are open with mode ORDWR.

SEE ALSO

       pipe(2)

SOURCE

       /sys/src/9/port/devpipe.c

																	   PIPE(3)

STREAM(3)						     Library Functions Manual							 STREAM(3)

NAME

       stream - a structure for communications

SYNOPSIS

       bind streamdevice dir

       dir/data
       dir/ctl

DESCRIPTION

       A  stream  is  not a device per se.  However, many devices use the streams package in the kernel to implement communications channels.  The
       properties described here are common to all such channels.

       All streams are represented by two standard files, ctl and data, plus any others the particular device wants to add.  Reading  and  writing
       the  data  file	receives  and sends data on the channel.  If the channel is message oriented, each write will represent a message and each
       read will return at most one message.  If the buffer given in a read is smaller than the message, subsequent reads will return the  remain-
       der of the message.

       Writing	textual command strings to the ctl file performs control operations on the stream.  The strings need not be null-terminated.  Each
       device may add to the control operations.  The common control operations are:

       hangup	     Hang up this stream.  Any subsequent writes will return an error.	The first subsequent read will return  0.   All  following
		     ones will return an error.

       push name     Push the module name onto the top of the stream.

       pop	     Pop the top module off the stream

       Reading	the  ctl  file returns a textual identifier for the stream.  This is used by multiplexed devices and its use is described with the
       particular device.

SEE ALSO

       pipe(3), dk(3), cons(3), async(3), fcall(3), ip(3), reboot(3)

SOURCE

       /sys/src/9/port/st*.c

																	 STREAM(3)