— make a FIFO file
char *path, mode_t
fd, const char
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.
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.
is passed the special value
AT_FDCWD (defined in
<fcntl.h>) in the
fd parameter, the current working directory is used
and the behavior is identical to a call to
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.
mkfifoat() will fail and no FIFO will be created
- The kernel has not been configured to support FIFOs.
- A component of the path prefix is not a directory.
- A component of a pathname exceeded
NAME_MAXcharacters, or an entire pathname (including the terminating NUL) exceeded
- A component of the path prefix does not exist.
- Search permission is denied for a component of the path prefix.
- Too many symbolic links were encountered in translating the pathname.
- The named file resides on a read-only file system.
- The named file exists.
- 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.
- There are no free inodes on the file system on which the FIFO is being created.
- 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.
- The user's quota of inodes on the file system on which the FIFO is being created has been exhausted.
- An I/O error occurred while making the directory entry or allocating the inode.
- An I/O error occurred while reading from or writing to the file system.
- path points outside the process's allocated address space.
mkfifoat() will fail if:
- The path argument specifies a relative path and the
fd argument is neither
AT_FDCWDnor a valid file descriptor.
- The path argument specifies a relative path and the fd argument is a valid file descriptor but it does not reference a directory.
- The path argument specifies a relative path but search permission is denied for the directory which the fd file descriptor references.
chmod(2), stat(2), umask(2)
mkfifoat() functions conform to
IEEE Std 1003.1-2008 (“POSIX.1”).
mkfifoat() function appeared in