EHPDFHeadlessDocumentError

This exception in HPDFHeadlessDocument exposes a read-only Code property of type THPDFHeadlessDiagnosticCode and a human-readable Message

The constructor accepts a diagnostic code and detail string; document callers should branch on the code instead of parsing message text

Operating-system I/O and codec failures may retain their native exception types; cancellation uses EHPDFOperationCancelled