Skip to main content

Tag

property Tag: NativeInt read write;

Example​

procedure MarkComponent(const Item: TComponent;
  const Marker: NativeInt);
begin
  Item.Tag := Marker;
end;

Usage​

Tag provides mutable NativeInt component metadata whose meaning is entirely defined by the surrounding application.

Parameters and result

Read/write NativeInt. Width follows the running process target, so it is 32-bit in a 32-bit process and 64-bit in a 64-bit process.

Behaviour

  • Default value is zero for a normally constructed component.
  • A value is meaningful only when the owning contract defines it.
  • Do not assume portability of large values between 32-bit and 64-bit Velox processes.
  • Do not use it as a pointer, credential, database key or durable Velox identifier without an explicit contract.

Errors and edge cases

A nil receiver fails. Assignments outside the running NativeInt range follow normal conversion/range behaviour.

Additional Technical Info​

Tag is a script-visible property declared on hidden ancestor TComponent. Visible descendant classes inherit it even though Classes/Common is intentionally omitted from the Velox and Docusaurus Code Library menus.

Tag is a general-purpose native-width signed integer stored on every TComponent. Delphi and Velox do not assign it a universal meaning.

Implementation trace

PascalScript directly reads and writes the native TComponent.Tag field. Object allocation zero-initialises it; native component streaming can persist published properties in contexts that actually stream the component.

Side effects and ownership

Writing changes live component metadata and may affect descendant/application code that also uses Tag.

Performance and concurrency

O(1), mutable and unsynchronised.

Remarks

This entry describes the installed Delphi Studio 37.0 terminal reached by the Velox-modified PascalScript registration. Free Pascal is linked for compatible Object Pascal context; where implementations differ, the traced Delphi behaviour above is authoritative. The example is source-reviewed and non-destructive except where the named operation is inherently destructive.

Related entries

  • DesignInfo is separate reserved designer metadata.
  • ClassName is diagnostic runtime type text, not a Tag schema.

External references

Created 2026-07-15