In this section:
This format is most useful when used with %tb (Bitmap Button) (see Bitmap button and toolbar). Using this format code, radio buttons and/or bitmap buttons (e.g. components of a toolbar) are ganged together. At any time at most one control in a gang will be switched on. The addition of a grave accent (`) makes sure that there is always one control switched on.
The parameter N must be present, and have a value greater than 1. N specifies the number of controls to be ganged. The argument list must contain N INTEGER arguments, that contain the N controlling integers. For example, in the toolbar example (see Bitmap button and toolbar), the three controls could be ganged together by modifying the code thus:
The ganging format code may be placed before or after the formats in which the control variables are actually used. A given variable may be used in more than one control. However, it is unusual for a variable to appear in more than one gang format for a given window. If it does then there must only be one variable that is common and the effect is to merge the two gang sets. If the grave accent is used on one of the gangs then it must be used on both.