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GetArrayLength

function GetArrayLength: Integer;

Example​

procedure ScriptEvent(var Value: Variant);
var
  Items: TStringArray;
begin
  SetArrayLength(Items, 3);
  Value := GetArrayLength(Items); // 3
end;

Usage​

GetArrayLength returns the element count of a supported static or dynamic array.

Parameters

NameTypeDescription
ArrArrayStatic or dynamic array whose element count is required. The argument is read, not resized or otherwise changed.

Returns

An Integer element count. An unallocated or zero-length dynamic array returns 0. A static array returns its declared fixed size.

Behaviour

The result is an element count, not the highest valid index or a byte size. For a non-empty zero-based array, the last valid index is GetArrayLength(Arr) - 1.

Errors

Unsupported or invalid runtime arguments cause the script executor to report that it could not call the procedure/function. The handler does not translate that failure to an element count.

Additional Technical Info​

GetArrayLength returns the number of elements in a static or dynamic array handled by the embedded Velox script runtime.

The effective Velox call is GetArrayLength(Arr). The generated Code Library declaration omits the synthetic Arr parameter because the compiler registers it separately as an untyped array argument.

Implementation

The modified PascalScript compiler creates this built-in and attaches the untyped Arr parameter. At runtime, Velox's shipped PascalScript handler inspects the argument's runtime type. It reads the compile-time size for a static array or the dynamic-array header length for a dynamic array.

Edge cases and quirks

  • Only the effective call with an array argument is useful, despite the parameterless generated declaration.
  • Unlike the wider Delphi and Free Pascal Length built-ins, GetArrayLength does not accept strings or other container types.
  • Static arrays can be measured but cannot be resized by SetArrayLength.
  • An unsupported argument type reaches the runtime's “Could not call proc” failure path rather than returning zero.

Side effects

The function only reads array metadata. It does not allocate, copy, resize or initialise elements.

Performance and concurrency

Length retrieval is constant time. The function performs no allocation and adds no locking; an array must not be resized concurrently through unsafe shared access.

Related entries

External references

Created 2026-07-15