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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | VERSIONS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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mkfifo(3) Library Functions Manual mkfifo(3)
mkfifo, mkfifoat - make a FIFO special file (a named pipe)
Standard C library (libc, -lc)
#include <sys/types.h>
#include <sys/stat.h>
int mkfifo(const char *path, mode_t mode);
#include <fcntl.h> /* Definition of AT_* constants */
#include <sys/stat.h>
int mkfifoat(int dirfd, const char *path, mode_t mode);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
mkfifoat():
Since glibc 2.10:
_POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
_ATFILE_SOURCE
mkfifo() makes a FIFO special file with name path. mode specifies
the FIFO's permissions. It is modified by the process's umask in
the usual way: the permissions of the created file are
(mode & ~umask).
A FIFO special file is similar to a pipe, except that it is
created in a different way. Instead of being an anonymous
communications channel, a FIFO special file is entered into the
filesystem by calling mkfifo().
Once you have created a FIFO special file in this way, any process
can open it for reading or writing, in the same way as an ordinary
file. However, it has to be open at both ends simultaneously
before you can proceed to do any input or output operations on it.
Opening a FIFO for reading normally blocks until some other
process opens the same FIFO for writing, and vice versa. See
fifo(7) for nonblocking handling of FIFO special files.
mkfifoat()
The mkfifoat() function operates in exactly the same way as
mkfifo(), except for the differences described here.
If path is relative, then it is interpreted relative to the
directory referred to by the file descriptor dirfd (rather than
relative to the current working directory of the calling process,
as is done by mkfifo() for a relative pathname).
If path is relative and dirfd is the special value AT_FDCWD, then
path is interpreted relative to the current working directory of
the calling process (like mkfifo()).
If path is absolute, then dirfd is ignored.
See openat(2) for an explanation of the need for mkfifoat().
On success mkfifo() and mkfifoat() return 0. On error, -1 is
returned and errno is set to indicate the error.
EACCES One of the directories in path did not allow search
(execute) permission.
EBADF (mkfifoat()) path is relative but dirfd is neither AT_FDCWD
nor a valid file descriptor.
EDQUOT The user's quota of disk blocks or inodes on the filesystem
has been exhausted.
EEXIST path already exists. This includes the case where path is
a symbolic link, dangling or not.
ENAMETOOLONG
Either the total size of path is greater than PATH_MAX, or
an individual filename component has a length greater than
NAME_MAX. In the GNU system, there is no imposed limit on
overall filename length, but some filesystems may place
limits on the length of a component.
ENOENT A directory component in path does not exist or is a
dangling symbolic link.
ENOSPC The directory or filesystem has no room for the new file.
ENOTDIR
A component used as a directory in path is not, in fact, a
directory.
ENOTDIR
(mkfifoat()) path is relative and dirfd is a file
descriptor referring to a file other than a directory.
EROFS path refers to a read-only filesystem.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│ mkfifo(), mkfifoat() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
It is implemented using mknodat(2).
POSIX.1-2008.
mkfifo()
POSIX.1-2001.
mkfifoat()
glibc 2.4. POSIX.1-2008.
mkfifo(1), close(2), open(2), read(2), stat(2), umask(2),
write(2), fifo(7)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Linux man-pages 6.15 2025-05-17 mkfifo(3)
Pages that refer to this page: mkfifo(1), mknod(2), open(2), umask(2), unlink(2), remove(3), fifo(7), pipe(7), signal-safety(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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