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 Table 102.

 

Table 102:

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