creat - create a new file

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

     int creat(const char *name, mode_t mode)

     This interface is made obsolete by open(2), it is equivalent to

          open(name, O_WRONLY | O_CREAT | O_TRUNC, mode)

     Creat creates a new file or prepares to rewrite an existing  file  called
     name,  given as the address of a null-terminated string.  If the file did
     not exist, it is given mode mode, as modified by the process's mode  mask
     (see  umask(2)).   Also  see  chmod(2)  for  the construction of the mode

     If the file did exist, its mode and owner  remain  unchanged  but  it  is
     truncated to 0 length.

     The file is also opened for writing, and its file descriptor is returned.

     The mode given is arbitrary; it need not allow writing.  This feature has
     been  used  in  the  past  by  programs  to construct a simple, exclusive
     locking mechanism.  It is replaced  by  the  O_EXCL  open  mode,  or  the
     advisory locking of the fcntl(2) facility.

     The value -1 is returned if an error occurs.  Otherwise, the call returns
     a non-negative descriptor that only permits writing.

     Creat will fail and the file will not be created or truncated if  one  of
     the following occur:

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

     [ENAMETOOLONG] The path name exceeds PATH_MAX characters.

     [ENOENT]       The named file does not exist.

     [ELOOP]        Too many symbolic links were  encountered  in  translating
                    the pathname.  (Minix-vmd)

     [EACCES]       Search permission is denied for a component  of  the  path

     [EACCES]       The file does not exist and the directory in which  it  is
                    to be created is not writable.

     [EACCES]       The file exists, but it is unwritable.

     [EISDIR]       The file is a directory.

     [EMFILE]       There are already too many files open.

     [ENFILE]       The system file table is full.

     [ENOSPC]       The directory in which the entry for the new file is being
                    placed  cannot  be extended because there is no space left
                    on the file system containing the directory.

     [ENOSPC]       There are no free inodes on the file system on  which  the
                    file is being created.

     [EROFS]        The named file resides on a read-only file system.

     [ENXIO]        The file is a character special or block special file, and
                    the associated device does not exist.

     [EIO]          An I/O error occurred while making the directory entry  or
                    allocating the inode.

     [EFAULT]       Name points outside the process's allocated address space.

     open(2), write(2), close(2), chmod(2), umask(2).