int open( const char *path, int access [, unsigned permis] )

	- prototype in io.h, also include stat.h & fcntl.h

	- open attribute flags are defined in fcntl.h
	- opens file "path" with access and optionally permis
	- access is a combination of the following ("permis" follows):

	  Read/Write Access Flags (mutually exclusive):
	   O_RDONLY	open read only
	   O_WRONLY	open write only
	   O_RDWR	open read/write

	  Other Access Mode Flags:
	   O_APPEND	file pointer is placed at EOF before each write
	   O_CREAT	if file doesn't exist, create with "permis" attributes
	   O_TRUNC	if exists, truncate length to zero, but leave file
			attributes unchanged
	   O_BINARY	binary mode
	   O_TEXT	text mode
	   O_EXCL	used with O_CREAT, error occurs if file already exists
	   O_NDELAY	UNIX only

	  Permission Attributes (if creating):
	   S_IWRITE	write permission
	   S_IREAD	read permission
	   S_IREAD | S_IWRITE read/write permission
	 
	- if O_BINARY nor O_TEXT is given, file is opened in translation
	  mode (O_TEXT) given by global variable _fmode
	- returns nonnegative number as file HANDLE, or -1 on error
	- see	sopen()