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diff --git a/man7/fifo.7 b/man7/fifo.7 new file mode 100644 index 0000000..f27dcc7 --- /dev/null +++ b/man7/fifo.7 @@ -0,0 +1,70 @@ +.\" SPDX-License-Identifier: Linux-man-pages-1-para +.\" +.\" This man page is Copyright (C) 1999 Claus Fischer. +.\" +.\" 990620 - page created - aeb@cwi.nl +.\" +.TH fifo 7 2023-07-15 "Linux man-pages 6.05.01" +.SH NAME +fifo \- first-in first-out special file, named pipe +.SH DESCRIPTION +A FIFO special file (a named pipe) is similar to a pipe, +except that it is accessed as part of the filesystem. +It can be opened by multiple processes for reading or +writing. +When processes are exchanging data via the FIFO, +the kernel passes all data internally without writing it +to the filesystem. +Thus, the FIFO special file has no +contents on the filesystem; the filesystem entry merely +serves as a reference point so that processes can access +the pipe using a name in the filesystem. +.PP +The kernel maintains exactly one pipe object for each +FIFO special file that is opened by at least one process. +The FIFO must be opened on both ends (reading and writing) +before data can be passed. +Normally, opening the FIFO blocks +until the other end is opened also. +.PP +A process can open a FIFO in nonblocking mode. +In this +case, opening for read-only succeeds even if no one has +opened on the write side yet and opening for write-only +fails with +.B ENXIO +(no such device or address) unless the other +end has already been opened. +.PP +Under Linux, opening a FIFO for read and write will succeed +both in blocking and nonblocking mode. +POSIX leaves this +behavior undefined. +This can be used to open a FIFO for +writing while there are no readers available. +A process +that uses both ends of the connection in order to communicate +with itself should be very careful to avoid deadlocks. +.SH NOTES +For details of the semantics of I/O on FIFOs, see +.BR pipe (7). +.PP +When a process tries to write to a FIFO that is not opened +for read on the other side, the process is sent a +.B SIGPIPE +signal. +.PP +FIFO special files can be created by +.BR mkfifo (3), +and are indicated by +.I ls\~\-l +with the file type \[aq]p\[aq]. +.SH SEE ALSO +.BR mkfifo (1), +.BR open (2), +.BR pipe (2), +.BR sigaction (2), +.BR signal (2), +.BR socketpair (2), +.BR mkfifo (3), +.BR pipe (7) |