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MKFIFO(2)                   BSD System Calls Manual                  MKFIFO(2)

NAME
     mkfifo, mkfifoat -- make a FIFO file

SYNOPSIS
     #include <&lt;sys/stat.h>&gt;

     int
     mkfifo(const char *path, mode_t mode);

     #include <&lt;sys/stat.h>&gt;
     #include <&lt;fcntl.h>&gt;

     int
     mkfifoat(int fd, const char *path, mode_t mode);

DESCRIPTION
     mkfifo() 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
     created.

     The mkfifoat() function is equivalent to mkfifo() except that where path
     specifies a relative path, the newly created FIFO is created relative to
     the directory associated with file descriptor fd instead of the current
     working directory.

     If mkfifoat() is passed the special value AT_FDCWD (defined in <fcntl.h>)
     in the fd parameter, the current working directory is used and the behav-
     ior is identical to a call to mkfifo().

RETURN VALUES
     Upon successful completion, the value 0 is returned; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     mkfifo() and mkfifoat() will fail and no FIFO will be created if:

     [EOPNOTSUPP]       The kernel has not been configured to support FIFOs.

     [ENOTDIR]          A component of the path prefix is not a directory.

     [ENAMETOOLONG]     A component of a pathname exceeded NAME_MAX charac-
                        ters, or an entire pathname (including the terminating
                        NUL) exceeded PATH_MAX bytes.

     [ENOENT]           A component of the path prefix does not exist.

     [EACCES]           Search permission is denied for a component of the
                        path prefix.

     [ELOOP]            Too many symbolic links were encountered in translat-
                        ing the pathname.

     [EROFS]            The named file resides on a read-only file system.

     [EEXIST]           The named file exists.

     [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 direc-
                        tory.

     [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]           path points outside the process's allocated address
                        space.

     Additionally, mkfifoat() will fail if:

     [EBADF]            The path argument specifies a relative path and the fd
                        argument is neither AT_FDCWD nor a valid file descrip-
                        tor.

     [ENOTDIR]          The path argument specifies a relative path and the fd
                        argument is a valid file descriptor but it does not
                        reference a directory.

     [EACCES]           The path argument specifies a relative path but search
                        permission is denied for the directory which the fd
                        file descriptor references.

SEE ALSO
     chmod(2), stat(2), umask(2)

STANDARDS
     The mkfifo and mkfifoat functions conform to IEEE Std 1003.1-2008
     (``POSIX.1'').

HISTORY
     The mkfifoat function appeared in OpenBSD 5.0.

BSD                             March 28, 2017                             BSD