erInvalidHeader

erInvalidHeader = 4

Example

function IsCompiledScriptHeaderFailure(const ErrorType: TIFException): Boolean;
begin
  Result := ErrorType = erInvalidHeader;
end;

Usage

erInvalidHeader indicates that compiled Velox scripting data has a missing, invalid or unsupported runtime header.

Formatting and exception state

ExceptionToString ignores Param and returns Invalid Header. The producer supplies no reason code, observed build number or expected range.

Additional Technical Info

erInvalidHeader is member ordinal 4 of TIFException, the script-visible declaration that is kept in exact ordinal alignment with PascalScript's runtime TPSError. Its sidebar position 25 is alphabetical navigation metadata and is not its enumeration value.

erInvalidHeader is emitted before the executor loads compiled types, procedures and variables. The current loader uses it for three distinct checks: the input is shorter than TPSHeader, the header magic does not equal PSValidHeader, or the stored PascalScript build number lies outside PSLowBuildSupport..PSCurrentBuildNo. The category therefore covers both damaged/non-PascalScript data and bytecode produced by an unsupported compiler/runtime generation. Loading stops before execution; the caller must provide compatible compiled script data or recompile from source.

Behavior, recovery and quirks

• Although erVersionError exists, current build-number mismatches use erInvalidHeader; the version-specific member has no explicit producer.
• This concerns the binary Velox scripting container, not a source-code include, EDI document header, HTTP header or dataset field.
• Do not retry the same bytes as though the error were transient. Confirm source/runtime provenance and regenerate the compiled script.
• 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