function CheckDoc: Integer; stdcall;
HRESULT _stdcall CheckDoc([out, retval] long* Value);
Function to check a signed PDF document, in order to see if the document was not changed after signing.
This function returns 0, 1, 2 or 3.
|0||No document loaded or error opening doc.|
|1||No Biodata found. Document has not been signed or Biodata is erased from the document.|
|2||Biodata found in document and document has not been manipulated.|
|3||Biodata or document has been manipulated.|
|4||the document is extended with additional data, it is manipulated|
If CheckDoc returns 3 or 4 you can not add new signatures to it, because the document has already been signed and was manipulated afterwards. The document is now invalid.