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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),
       character 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  directory;
       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
       behavior  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_resolution(7)

COLOPHON

       This  page  is  part of release 3.27 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/.