mkfifo

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

NAME
     mkfifo, mkfifoat — make a fifo file

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/types.h>
     #include <sys/stat.h>

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

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

DESCRIPTION
     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 created.

     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 mkfifo().

RETURN VALUES
     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
     error.

ERRORS
     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 system.

     [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 more
                        information.

     [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 directory.

     [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 fail
     if:

     [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 a
                        directory.

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

STANDARDS
     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.

HISTORY
     The mkfifoat() system call appeared in FreeBSD 8.0.

BSD                              April 10, 2008                              BSD