MKNOD(2)						     Linux Programmer's Manual							  MKNOD(2)

NAME

       mknod - create a special or ordinary file

SYNOPSIS

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

       int mknod(const char *pathname, mode_t mode, dev_t dev);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       mknod():
	   _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

DESCRIPTION

       The  system  call mknod() creates a file system node (file, device special file or named pipe) named pathname, with attributes specified by
       mode and dev.

       The mode argument specifies both the permissions to use and the type of node to be created.  It should be a combination (using bitwise  OR)
       of one of the file types listed below and the permissions for the new node.

       The permissions are modified by the process's umask in the usual way: the permissions of the created node are (mode & ~umask).

       The  file type must be one of S_IFREG, S_IFCHR, S_IFBLK, S_IFIFO or S_IFSOCK to specify a regular file (which will be created empty), char-
       acter special file, block special file, FIFO (named pipe), or UNIX domain socket, respectively.	(Zero file  type  is  equivalent  to  type
       S_IFREG.)

       If  the file type is S_IFCHR or S_IFBLK then dev specifies the major and minor numbers of the newly created device special file (makedev(3)
       may be useful to build the value for dev); otherwise it is ignored.

       If pathname already exists, or is a symbolic link, this call fails with an EEXIST error.

       The newly created node will be owned by the effective user ID of the process.  If the directory containing the node  has  the  set-group-ID
       bit  set,  or  if the file system is mounted with BSD group semantics, the new node will inherit the group ownership from its parent direc-
       tory; otherwise it will be owned by the effective group ID of the process.

RETURN VALUE

       mknod() returns zero on success, or -1 if an error occurred (in which case, errno is set appropriately).

ERRORS

       EACCES The parent directory does not allow write permission to the process, or one of the directories in the path prefix  of  pathname  did
	      not allow search permission.  (See also path_resolution(7).)

       EEXIST pathname already exists.	This includes the case where pathname is a symbolic link, dangling or not.

       EFAULT pathname points outside your accessible address space.

       EINVAL mode requested creation of something other than a regular file, device special file, FIFO or socket.

       ELOOP  Too many symbolic links were encountered in resolving pathname.

       ENAMETOOLONG
	      pathname was too long.

       ENOENT A directory component in pathname does not exist or is a dangling symbolic link.

       ENOMEM Insufficient kernel memory was available.

       ENOSPC The device containing pathname has no room for the new node.

       ENOTDIR
	      A component used as a directory in pathname is not, in fact, a directory.

       EPERM  mode  requested  creation  of  something	other than a regular file, FIFO (named pipe), or UNIX domain socket, and the caller is not
	      privileged (Linux: does not have the CAP_MKNOD capability); also returned if the file system containing pathname	does  not  support
	      the type of node requested.

       EROFS  pathname refers to a file on a read-only file system.

CONFORMING TO

       SVr4, 4.4BSD, POSIX.1-2001 (but see below).

NOTES

       POSIX.1-2001  says: "The only portable use of mknod() is to create a FIFO-special file.	If mode is not S_IFIFO or dev is not 0, the behav-
       ior of mknod() is unspecified."	However, nowadays one should never use mknod() for this purpose; one  should  use  mkfifo(3),  a  function
       especially defined for this purpose.

       Under Linux, this call cannot be used to create directories.  One should make directories with mkdir(2).

       There are many infelicities in the protocol underlying NFS.  Some of these affect mknod().

SEE ALSO

       chmod(2),  chown(2), fcntl(2), mkdir(2), mknodat(2), mount(2), socket(2), stat(2), umask(2), unlink(2), makedev(3), mkfifo(3), path_resolu-
       tion(7)

COLOPHON

       This page is part of release 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2010-09-20								  MKNOD(2)