Provided by: freebsd-manpages_12.2-1_all 
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.
[EINTEGRITY] Corrupted data was detected while reading from 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.