mkfifo(3) - Linux manual page (original) (raw)
mkfifo(3) Library Functions Manual mkfifo(3)
NAME top
mkfifo, mkfifoat - make a FIFO special file (a named pipe)LIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#include <sys/types.h>**
**#include <sys/stat.h>**
**int mkfifo(const char ***_pathname_**, mode_t** _mode_**);**
**#include <fcntl.h>** /* Definition of AT_* constants */
**#include <sys/stat.h>**
**int mkfifoat(int** _dirfd_**, const char ***_pathname_**, 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_SOURCEDESCRIPTION top
**mkfifo**() makes a FIFO special file with name _pathname_. _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)](../man7/fifo.7.html) 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 the pathname given in _pathname_ 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 _pathname_ is relative and _dirfd_ is the special value **AT_FDCWD**,
then _pathname_ is interpreted relative to the current working
directory of the calling process (like **mkfifo**()).
If _pathname_ is absolute, then _dirfd_ is ignored.
See [openat(2)](../man2/openat.2.html) for an explanation of the need for **mkfifoat**().RETURN VALUE top
On success **mkfifo**() and **mkfifoat**() return 0. On error, -1 is
returned and _[errno](../man3/errno.3.html)_ is set to indicate the error.ERRORS top
**EACCES** One of the directories in _pathname_ did not allow search
(execute) permission.
**EBADF** (**mkfifoat**()) _pathname_ 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** _pathname_ already exists. This includes the case where
_pathname_ is a symbolic link, dangling or not.
**ENAMETOOLONG**
Either the total length of _pathname_ 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 _pathname_ 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 _pathname_ is not, in
fact, a directory.
**ENOTDIR**
(**mkfifoat**()) _pathname_ is a relative pathname and _dirfd_ is a
file descriptor referring to a file other than a directory.
**EROFS** _pathname_ refers to a read-only filesystem.ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ **Interface** │ **Attribute** │ **Value** │
├──────────────────────────────────────┼───────────────┼─────────┤
│ **mkfifo**(), **mkfifoat**() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘VERSIONS top
It is implemented using [mknodat(2)](../man2/mknodat.2.html).STANDARDS top
POSIX.1-2008.HISTORY top
**mkfifo**()
POSIX.1-2001.
**mkfifoat**()
glibc 2.4. POSIX.1-2008.SEE ALSO top
[mkfifo(1)](../man1/mkfifo.1.html), [close(2)](../man2/close.2.html), [open(2)](../man2/open.2.html), [read(2)](../man2/read.2.html), [stat(2)](../man2/stat.2.html), [umask(2)](../man2/umask.2.html),
[write(2)](../man2/write.2.html), [fifo(7)](../man7/fifo.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 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)