[fpc-pascal] Access Violation When SetLength(DynArray, Value)

[Sven Barth]

Am 10.09.2022 um 01:41 schrieb James Richters:
> I thought I would make my own IncArray() function:
> Procedure IncArray(Var TheArray);
> Begin
>     SetLength(TheArray,Length(TheArray)+1);
> End;
>
> But I get a 'Type Mismatch'  Any ideas how this could be done?  Is this even possible without specifying the exact type of array?

You can't simply use a formal parameter for that as SetLength requires 
information about the type which is missing in that case. What you can 
do is use a generic procedure:

=== code begin ===

generic procedure IncArray<T>(var aArray: specialize TArray<T>);
begin
   SetLength(aArray, Length(aArray) + 1);
end;

var
   arr: array of LongInt;
begin
   arr := [1, 2, 3];
   specialize IncArray<LongInt>(arr);
end.

=== code end ===

In 3.3.1 you can also enable the modeswitch 
ImplicitFunctionSpecialization and you can then simply use the following 
as the compiler is able to derive the type to specialize with:

=== code begin ===

IncArray(arr);

=== code end ===

Regards,
Sven