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MKFIFO(2)		  FreeBSD System Calls Manual		     MKFIFO(2)

     mkfifo, mkfifoat -- make a	fifo file

     Standard C	Library	(libc, -lc)

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

     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 ac-
     cess 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	de-
     scriptor fd instead of the	current	working	directory.  If mkfifoat() is
     passed the	special	value AT_FDCWD in the fd parameter, the	current	work-
     ing 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 permis-
			sion, or write permission is denied on the parent di-
			rectory	of the fifo to be created.

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

     [EROFS]		The named file would reside on a read-only file	sys-

     [EEXIST]		The named file exists.

     [EPERM]		The parent directory of	the named file has its im-
			mutable	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 direc-

     [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.

     [EINTEGRITY]	Corrupted data was detected while reading from the
			file system.

     [EFAULT]		The path argument points outside the process's allo-
			cated 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.

     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.

FreeBSD	13.0			March 30, 2020			  FreeBSD 13.0


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