MSC: unsigned _dos_close( int handle )

	- prototype in dos.h

	- handle is standard DOS file handle attained through _dos_creat(),
	  _dos_creat(), _dos_creatnew(), _dos_open(), dup(), open()
	- returns 0 on success or DOS error code on failure
	- does not write a Ctrl-Z to a text file on closing
	- see	INT 21,3E