FOPEN program instruction FOPEN program instruction Syntax FOPEN (logical_unit, mode ) attribute_list Function Create and open a new graphics window or TCP connection, or open an existing graphics window for subsequent input or output. Open a graphics icon for definition. Usage Considerations The logical unit must be attached before an open operation will succeed. Parameters logical_unit Real value, variable, or expression (interpreted as an integer) that defines the logical unit number assigned to the window or TCP device. (See the ATTACH instruction for a description of unit numbers.) mode Optional expression that applies only to TCP logical units and selects the type of TCP connection:
0 = Client mode, 16 = Server mode. attribute_list List of string constants, variables, and expressions; real values, variables, and expressions; and format specifiers used to assign a name to the window and to define some of the characteristics of the window. When opening a TCP connection in server mode, this string defines the characteristics of the server. When opening a connection in client mode, the string defines the name of the server in addition to characteristics of the connection. The attribute list (which is processed like an output specification for the TYPE instruction) is used to compose a single string that is passed to the window manager or TCP driver.
The string must begin with the name of the window and can optionally contain keyword attributes that define characteristics of the window. The string must not exceed 512 characters. NOTE: An eV+ string literal or string variable cannot exceed eV+Language Reference Guide, v2.x, 18319-000 Rev A Page 244