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Programming Interfaces
External Program Interfaces : Using COM Objects in ABL : Accessing COM object properties and methods : Specifying options for properties and method parameters
 
Specifying options for properties and method parameters
ABL allows you to specify a variety of data-type specifier and mode options for passing COM object method parameters and setting COM object properties (see Propertyand method syntax). Data-type specifier options specify a data type mapping between COM data types and ABL data types; mode options specify how a method parameter is passed (whether for input or output). Thus:
*The data-type specifier options in Table 60 dictate COM data type conversions for passing method input parameters and setting properties that are different than the defaults. (For more information on COM data-type conversion, see COMObject Data Type Mapping)
*The type options BY-POINTER and BY-VARIANT-POINTER specify additional information for passing method parameters.
*The mode options OUTPUT and INPUT-OUTPUT specify how the method parameter is used.
One of the essential criteria that determines when and how you might have to use data-type specifier and mode options is the Type Library provided with a COM object implementation.
* Understanding a COM object Type Library
* Using data-type specifier options
* Using data-type specifiers for properties
* Using data-type specifiers for method parameters
* Using mode options for method parameters