erInvalidOpcodeParameter

erInvalidOpcodeParameter = 6

Example

function IsInvalidBytecodeOperand(const ErrorType: TIFException): Boolean;
begin
  Result := ErrorType = erInvalidOpcodeParameter;
end;

Usage

erInvalidOpcodeParameter indicates that a recognised Velox scripting bytecode operation contains an unsupported or invalid selector or operand.

Formatting and exception state

ExceptionToString ignores Param and returns Invalid Opcode Parameter. Automatic producer sites do not include the bad selector or operand in Param.

Additional Technical Info

erInvalidOpcodeParameter is member ordinal 6 of TIFException, the script-visible declaration that is kept in exact ordinal alignment with PascalScript's runtime TPSError. Its sidebar position 27 is alphabetical navigation metadata and is not its enumeration value.

erInvalidOpcodeParameter means the outer bytecode operation was recognised but a subordinate operation code, comparison selector, conversion/cast selector or other encoded operand was not valid for that instruction. The runtime emits it from several operator and dispatch switch defaults. It is distinct from erInvalidOpcode, where the primary operation byte itself is unknown, and from ErTypeMismatch, where the encoded operation is valid but the runtime values/types are incompatible.

Behavior, recovery and quirks

• The category normally points to corrupt or incompatible compiled script data or a Velox scripting defect rather than end-user configuration.
• Procedure and bytecode position are the essential diagnostic coordinates; keep the exact compiled artifact and product revision.
• Already completed host-side effects are not rolled back when the executor stops.
• Exception transfer is not a database, dataset, filesystem or external-system transaction. Any earlier side effect remains unless the called API or surrounding Flow provides an explicit rollback contract.
• Do not persist the numeric ordinal as an integration contract. Store the member name, formatted message, parameter and relevant procedure/position with the Velox version.

Related Code Library entries

• TIFException - complete member order and shared VM-error contract.
• ExceptionType - read the category saved for the current executor/handler.
• ExceptionParam - read its associated parameter before state changes.
• ExceptionProc and ExceptionPos - locate the compiled procedure and instruction.
• ExceptionToString - exact text/parameter mapping for every category.
• RaiseException and RaiseLastException - create a new error or preserve the caught one.
• try..except - handler availability, propagation and rollback boundaries.

External references

• RemObjects PascalScript uPSRuntime.pas - upstream runtime taxonomy and executor context; the modified source shipped with Velox is authoritative for current behavior.

Created 2026-07-15