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  filesystem  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  filesystem  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).)

       EDQUOT The user's quota of disk blocks or inodes on the filesystem has been exhausted.

       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 filesystem containing pathname does not support the type of node requested.

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

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 3.54 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/.