gosub

Macro Command Help

GOSUB

Macro Command Name	Menu Path	Link to Command Table
GOSUB	Access via macro or menu only	Click here

Introduction
Notes
Examples
Errors

Introduction

Stores the current macro position and branches to a specified command label within a macro or menu.

How to use

Format : GOSUB <LABEL NAME>

A subroutine is any portion of a macro or menu that :-

Begins on a label line !<LABEL NAME>:
Ends with a !RETURN statement.

The label may consist of up to 16 characters, and must be present in the current macro/menu or an error will result. Labels are denoted by using the special char ":" (colon).

Notes

When an executing macro or menu encounters a GOSUB statement, it saves the current line number and then branches to the specified label. Execution continues normally until a RETURN statement is executed, at which point the macro or menu jumps back and resumes execution at the line after the GOSUB statement.

Execution of a RETURN statement without a corresponding GOSUB will give an error. For nested macros, the RETURN statement must be in the same macro or menu as the corresponding GOSUB statement. Up to sixteen RETURN's may be pending at any time within the currently executing macro or menu.

Example

The following macro fragment will divert macro processing to the label "PLOT_INIT". When "!RETURN" is encountered, control will be diverted to the next line after "!GOSUB"

!GOSUB PLOT_INIT

.....................

!PLOT_INIT:REM - Subroutine : clean plot

.....................

!RETURN

Error and Warning Messages

Message	Description	Solution
>>> ERR 75 <<< ( 3) IN ADDSFT >>> Incorrect label XXXX in GOSUB XXXX or XXXX not found <<< !gosub PLOT_INIT >>> Macro "plot ", line 54.	The label PLOT_INIT encountered within the macro plot.mac at line 54 cannot be found within the macro.	Check the name and syntax of the listed label.