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MKNOD(P)			    POSIX Programmer's Manual				 MKNOD(P)

NAME
       mknod - make a directory, a special file, or a regular file

SYNOPSIS
       #include <sys/stat.h>

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

DESCRIPTION
       The  mknod()  function shall create a new file named by the pathname to which the argument
       path points.

       The file type for path is OR'ed into the mode argument, and the application  shall  select
       one of the following symbolic constants:

			       Name	 Description
			       S_IFIFO	 FIFO-special
			       S_IFCHR	 Character-special (non-portable)
			       S_IFDIR	 Directory (non-portable)
			       S_IFBLK	 Block-special (non-portable)
			       S_IFREG	 Regular (non-portable)

       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 behavior of mknod() is unspecified.

       The permissions for the new file are OR'ed into the mode argument,  and	may  be  selected
       from any combination of the following symbolic constants:

			  Name	   Description
			  S_ISUID  Set user ID on execution.
			  S_ISGID  Set group ID on execution.
			  S_IRWXU  Read, write, or execute (search) by owner.
			  S_IRUSR  Read by owner.
			  S_IWUSR  Write by owner.
			  S_IXUSR  Execute (search) by owner.
			  S_IRWXG  Read, write, or execute (search) by group.
			  S_IRGRP  Read by group.
			  S_IWGRP  Write by group.
			  S_IXGRP  Execute (search) by group.
			  S_IRWXO  Read, write, or execute (search) by others.
			  S_IROTH  Read by others.
			  S_IWOTH  Write by others.
			  S_IXOTH  Execute (search) by others.
			  S_ISVTX  On directories, restricted deletion flag.

       The  user ID of the file shall be initialized to the effective user ID of the process. The
       group ID of the file shall be initialized to either the effective group ID of the  process
       or the group ID of the parent directory. Implementations shall provide a way to initialize
       the file's group ID to the group ID of the parent directory. Implementations may, but need
       not, provide an implementation-defined way to initialize the file's group ID to the effec-
       tive group ID of the calling process. The owner, group, and other permission bits of  mode
       shall  be  modified  by	the  file mode creation mask of the process. The mknod() function
       shall clear each bit whose corresponding bit in the file mode creation mask of the process
       is set.

       If path names a symbolic link, mknod() shall fail and set errno to [EEXIST].

       Upon  successful  completion,  mknod()  shall  mark for update the st_atime, st_ctime, and
       st_mtime fields of the file. Also, the st_ctime and st_mtime fields of the directory  that
       contains the new entry shall be marked for update.

       Only  a	process  with appropriate privileges may invoke mknod() for file types other than
       FIFO-special.

RETURN VALUE
       Upon successful completion, mknod() shall return 0. Otherwise, it shall return -1, the new
       file shall not be created, and errno shall be set to indicate the error.

ERRORS
       The mknod() function shall fail if:

       EACCES A  component  of	the  path prefix denies search permission, or write permission is
	      denied on the parent directory.

       EEXIST The named file exists.

       EINVAL An invalid argument exists.

       EIO    An I/O error occurred while accessing the file system.

       ELOOP  A loop exists in symbolic links encountered during resolution of the path argument.

       ENAMETOOLONG
	      The length of a pathname exceeds {PATH_MAX} or a pathname component is longer  than
	      {NAME_MAX}.

       ENOENT A  component  of the path prefix specified by path does not name an existing direc-
	      tory or path is an empty string.

       ENOSPC The directory that would contain the new file cannot be extended or the file system
	      is out of file allocation resources.

       ENOTDIR
	      A component of the path prefix is not a directory.

       EPERM  The  invoking process does not have appropriate privileges and the file type is not
	      FIFO-special.

       EROFS  The directory in which the file is to be created is located  on  a  read-only  file
	      system.

       The mknod() function may fail if:

       ELOOP  More  than  {SYMLOOP_MAX}  symbolic links were encountered during resolution of the
	      path argument.

       ENAMETOOLONG
	      Pathname resolution of a symbolic link produced an intermediate result whose length
	      exceeds {PATH_MAX}.

       The following sections are informative.

EXAMPLES
   Creating a FIFO Special File
       The  following  example	shows how to create a FIFO special file named /home/cnd/mod_done,
       with read/write permissions for owner, and with read permissions for group and others.

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

	      dev_t dev;
	      int   status;
	      ...
	      status  = mknod("/home/cnd/mod_done", S_IFIFO | S_IWUSR |
		  S_IRUSR | S_IRGRP | S_IROTH, dev);

APPLICATION USAGE
       The mkfifo() function is preferred over this function for making FIFO special files.

RATIONALE
       The POSIX.1-1990 standard required that the group ID of a newly created file be set to the
       group  ID  of  its  parent directory or to the effective group ID of the creating process.
       FIPS 151-2 required that implementations provide a way to have the group ID be set to  the
       group ID of the containing directory, but did not prohibit implementations also supporting
       a way to set the group ID to the effective group ID of the  creating  process.  Conforming
       applications  should not assume which group ID will be used. If it matters, an application
       can use chown() to set the group ID after the file is created,  or  determine  under  what
       conditions the implementation will set the desired group ID.

FUTURE DIRECTIONS
       None.

SEE ALSO
       chmod()	,  creat()  ,  exec() , mkdir() , mkfifo() , open() , stat() , umask() , the Base
       Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h>

COPYRIGHT
       Portions of this text are reprinted and	reproduced  in	electronic  form  from	IEEE  Std
       1003.1,	2003  Edition,	Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003					 MKNOD(P)
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