The GOPEN subroutine is a graphical call that starts a new graphics segment.

The arguments to the GOPEN subroutine are as follows:

segment-name

is a character matrix or quoted literal that specifies the name of a graphics segment.

replace

is a numeric argument.

description

is a character matrix or quoted text string with a maximum length of 40 characters.

The GOPEN subroutine starts a new graphics segment. The window and viewport are reset to the default values () in both cases. Any attribute modified by using a GSET call is reset to its default value, which is set by the attribute’s corresponding GOPTIONS value.

A nonzero value for replace indicates that the new segment should replace the first found segment with the same name, and zero indicates otherwise. If you do not specify the replace flag, the flag set by a previous GSTART call is used. By default, the GSTART subroutine sets the flag to NOREPLACE.

The description is a text string of up to 40 characters that you want to store with the segment to describe the graph.

Two graphs cannot have the same name. If you try to create a named segment twice, the second segment is given an automatically generated name.

The following statement opens a new segment named "cosine", replaces the existing segment of the same name, and attaches a description to the segment:

call gopen("cosine", 1, "Graph of Cosine Curve");