Michael Van Canneyt via fpc-pascal wrote:
28. The documentation for macpas "UNIV" is missing ?
I have no idea what this is ?
UNIV is macpas specific (as mentioned in Appendix D.6 of the Programmer's
Manual)
With UNIV,
... ":" [ "ARRAY" "OF" ] type-identifier ...
in the syntax diagrams, becomes
... ":" [ "ARRAY" "OF" | UNIV ] type-identifier ...
The modifier UNIV indicates that the actual parameter can be of any type that has the same
byte-size as the formal parameter.
Example:
procedure HDispose( var theHandle: univ Handle); .....
which saves a value-type-cast when calling HDispose with handles that are not (precisely) of type
Handle.
Another use of UNIV is type-compatibility of procedural parameters. For example
with
function BinaryFind
( theValuePtr : univ UnivPtr;
theFirstIndex : Int32;
theLastIndex : Int32;
function SmallerThan
( theIndex : Int32;
theValuePtr : univ UnivPtr): boolean;
function EqualTo
( theIndex : Int32;
theValuePtr : univ UnivPtr): boolean;
var theFoundIndex : Int32): boolean;
we can call BinaryFind as follows
theFoundFlag := BinaryFind
( @theCmdID, 1, kCmdCount, CmdIDSmallerThan, CmdIDEqualTo,
where
function CmdIDSmallerThan
( theIndex : Int32;
theValuePtr : CmdIDPtr): boolean; .....
and
function CmdIDEqualTo
( theIndex : Int32;
theValuePtr : CmdIDPtr): boolean; ...
because CmdIDPtr is through UNIV type-compatible with
theValuePtr : univ UnivPtr
Regards,
Adriaan van Os
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