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MKNOD(2)		   Linux Programmers Manual		     MKNOD(2)

       mknod - create a special or ordinary file


       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

       The  system  call mknod() creates a file system node (file, device spe
       cial 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

       The permissions are modified by the processs 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

       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; otherwise it is

       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 directory; other
       wise it will be owned by the effective group ID of the process.

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

       EACCES The parent directory does not allow write permission to the pro
	      cess, 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.

	      pathname was too long.

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

       ENOMEM Insufficient kernel memory was available.

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

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

       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.

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

       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  espe
       cially 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().

       chmod(2),   chown(2),   fcntl(2),   mkdir(2),   mknodat(2),   mount(2),
       socket(2), stat(2), umask(2), unlink(2), mkfifo(3), path_resolution(7)

       This page is part of release 3.05 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				  2007-07-26			      MKNOD(2)

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