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EmptyGuid

Function EmptyGuid: TGuid

Example​

procedure ScriptEvent(var Value: variant);
var
  Identifier: TGuid;
begin
  Identifier := EmptyGuid;
  Value := IsEmptyGuid(Identifier); // True
end;

Usage​

EmptyGuid returns the all-zero GUID_NULL value as a TGuid record.

Returns

A value copy of GUID_NULL, equivalent to {00000000-0000-0000-0000-000000000000} when formatted by Velox GUIDToString.

Important usage notes

  • An empty GUID is still a syntactically valid GUID value and can be stored or formatted.
  • It does not carry a database null flag. GUIDToSQL quotes it as a zero-GUID literal rather than returning SQL NULL.
  • It is not evidence that a variable was never initialized; application code can intentionally assign the same all-zero value.
  • Do not compare a formatted string manually when IsEmptyGuid can compare the record directly.

Additional Technical Info​

EmptyGuid returns Delphi's GUID_NULL constant: a 16-byte TGuid record whose every field and byte is zero. It is a sentinel value, not a null reference, unassigned variable, empty string or SQL NULL.

The example is fictional, deterministic and source-reviewed. It was not executed by the documentation workflow.

Implementation

The common import binds directly to vxCommon.EmptyGuid. The function consists of Result := GUID_NULL. There is no allocation, parsing, operating-system call or lazy initialization.

Value structure

TGuid comprises D1: LongWord, D2: Word, D3: Word and D4: array[0..7] of Byte. GUID_NULL sets all of them to zero. Returning the record copies those 16 bytes into the caller's value.

Side effects and errors

None. The function reads a compile-time/RTL constant and cannot fail under ordinary execution.

Performance and concurrency

Constant-time 16-byte value return with no shared mutable state.

Related entries

External references

Created 2026-07-15