Provided by: freebsd-manpages_8.2-1_all
mkfifo, mkfifoat — make a fifo file
Standard C Library (libc, -lc)
mkfifo(const char *path, mode_t mode);
mkfifoat(int fd, const char *path, mode_t mode);
The mkfifo() system call creates a new fifo file with name path. The
access permissions are specified by mode and restricted by the umask(2)
of the calling process.
The fifo's owner ID is set to the process's effective user ID. The
fifo's group ID is set to that of the parent directory in which it is
The mkfifoat() system call is equivalent to mkfifo() except in the case
where path specifies a relative path. In this case the newly created
FIFO is created relative to the directory associated with the file
descriptor fd instead of the current working directory. If mkfifoat() is
passed the special value AT_FDCWD in the fd parameter, the current
working directory is used and the behavior is identical to a call to
The mkfifo() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The mkfifo() system call will fail and no fifo will be created if:
[ENOTSUP] The kernel has not been configured to support fifo's.
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[ENOENT] A component of the path prefix does not exist.
[EACCES] A component of the path prefix denies search
permission, or write permission is denied on the
parent directory of the fifo to be created.
[ELOOP] Too many symbolic links were encountered in
translating the pathname.
[EROFS] The named file would reside on a read-only file
[EEXIST] The named file exists.
[EPERM] The parent directory of the named file has its
immutable flag set, see the chflags(2) manual page for
[ENOSPC] The directory in which the entry for the new fifo is
being placed cannot be extended because there is no
space left on the file system containing the
[ENOSPC] There are no free inodes on the file system on which
the fifo is being created.
[EDQUOT] The directory in which the entry for the new fifo is
being placed cannot be extended because the user's
quota of disk blocks on the file system containing the
directory has been exhausted.
[EDQUOT] The user's quota of inodes on the file system on which
the fifo is being created has been exhausted.
[EIO] An I/O error occurred while making the directory entry
or allocating the inode.
[EIO] An I/O error occurred while reading from or writing to
the file system.
[EFAULT] The path argument points outside the process's
allocated address space.
In addition to the errors returned by the mkfifo(), the mkfifoat() may
[EBADF] The path argument does not specify an absolute path
and the fd argument is neither AT_FDCWD nor a valid
file descriptor open for searching.
[ENOTDIR] The path argument is not an absolute path and fd is
neither AT_FDCWD nor a file descriptor associated with
chflags(2), chmod(2), mknod(2), stat(2), umask(2)
The mkfifo() system call is expected to conform to ISO/IEC 9945-1:1990
(“POSIX.1”). The mkfifoat() system call follows The Open Group Extended
API Set 2 specification.
The mkfifoat() system call appeared in FreeBSD 8.0.