int sopen( const char *path, int access, int shflag, int mode )

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

	- actually a macro defined:  open( path, (access | shflag), mode )
	- opens file "path" and prepares it for shared I/O
	- sharing mode is determined using access, shflag and mode
	- 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

	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 non-negative number as file handle, or -1 on error