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       mknod - create a special or ordinary file


       #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)):

           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||


       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.


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


       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.

              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.

              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.


       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 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().


       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)


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