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ABL Reference
Handle Attributes and Methods Reference : RETURN-VALUE-DLL-TYPE attribute
 

RETURN-VALUE-DLL-TYPE attribute

Specifies the expected data type returned from a Windows Dynamic Link Library (DLL) routine.
Data type: CHARACTER
Access: Readable/Writable
Applies to: Call object handle
The RETURN-VALUE-DLL-TYPE attribute must be assigned before invoking the call object's INVOKE( ) method. After invocation, RETURN-VALUE contains an equivalent ABL data type which matches RETURN-VALUE-DLL-TYPE as shown in the following table.
Table 103. Mapping RETURN-VALUE-DLL-TYPE to RETURN-VALUE
RETURN-VALUE-DLL-TYPE
RETURN-VALUE
BYTE
INTEGER
CHARACTER
CHARACTER
DOUBLE
DECIMAL
FLOAT
DECIMAL
INT64
INT64
LONG
INTEGER
MEMPTR
MEMPTR
SHORT
INTEGER
UNSIGNED-LONG
INT64
UNSIGNED-SHORT
INTEGER
For example, if a DLL function is expected to return a LONG value, then RETURN-VALUE-DLL-TYPE is set to "LONG" before executing the INVOKE( ) method. After the invocation, RETURN-VALUE-DATA-TYPE has a value of "INTEGER" and RETURN-VALUE contains an INTEGER value.
If RETURN-VALUE-DLL-TYPE is not set, the DLL routine's return value is ignored, and RETURN-VALUE is set to the Unknown value (?).

See also

INVOKE( ) method (Handle), RETURN-VALUE attribute