Structure_Abort

See Also: Structure_End, Structure_Start

Purpose

To terminate a table structure operation without completing it.

Syntax

Structure_Abort tableNum

Argument Explanation

tableNum

The variable containing the handle from the corresponding Structure_Start.

What It Does

This command can be used when constructing error handling routines. The Structure_Abort command will undo any structure operations that have been done since the last Structure_Start.

Structure_Start hTable

    // Create an index, and set its attributes. Also process any errors.

    Create_Index hTable at iIndex

    on error gosub bad_structure

    Set_Attribute DF_INDEX_SEGMENT_FIELD of hTable iIndex 1 to 2

    Set_Attribute DF_INDEX_SEGMENT_FIELD of hTable iIndex 2 to 4

    Set_Attribute DF_INDEX_SEGMENT_FIELD of hTable iIndex 3 to 0

Structure_End hTable

bad_structure:

    showln "An error has occurred while creating the index. Program will abort."

    Structure_Abort hTable

    abort

return

This example will call the error-handling procedure bad_structure, if any errors occur during the creation of the index.

Notes

• After a restructure, tableNum contains a table handle rather than the table number it was passed before the restructure. Therefore, an open tableNum statement after a restructure will return an error. It is good practice either to create a separate variable to pass to Structure_Start for tableNum or to perform restructures in procedures that use a local variable for the parameter.