Set the file permission bits of the created fifos to the specified mode, ignoring the umask(2) of the calling process. The mode argument takes any format that can be specified to the chmod(1) command. If a symbolic mode is specified, the op symbols "+" (plus) and "-" (hyphen) are interpreted relative to an assumed initial mode of "a=rw" (read and write permissions for all).
If the -m option is not specified, fifos are created with mode 0666 modified by the umask(2) of the calling process. The mkfifo utility requires write permission in the parent directory.