How to handle libnodave error message with Delphi?

Question

I have a function that reads some values from Siemens PLC using libnodave.dll and nodave unit but I cannot figure out the error output. I am on purpose forcing to go in error and what I get from AError := string(daveStrerror(readResult)); is an incomprehensible message:

'桴'#$2065'敤楳敲'#$2064'摡牤獥'#$2073'獩戠祥湯'#$2064'楬業⁴潦'#$2072'桴獩倠䍌'

Maybe 2064/2065/2073/2072 all represent a different error code which I have to handle independently? And why chinese? My machine is set up in Italian language.

I guess, that unit is not made for Unicode and your are using a Delphi version above D2007. — Uwe Raabe
– Uwe Raabe, Commented Feb 8, 2024 at 10:21
Please be aware that these values are hex values because the of $ sign! — DelphiCoder
– DelphiCoder, Commented Feb 8, 2024 at 11:10
This is just the classic issue of interpreting UTF-16 text as if it were 8 bit ANSI text. Which Delphi version are you using? — David Heffernan
– David Heffernan, Commented Feb 8, 2024 at 11:16
Sorry, I misspoke. It's the other way around. This is 8 bit text and you are treating it as UTF-16. Do you know what encoding this library is using? Is it ANSI or UTF-8? And are you familiar with text encodings?> — David Heffernan
– David Heffernan, Commented Feb 8, 2024 at 11:19

Uwe Raabe · Accepted Answer · 2024-02-08 11:54:29Z

2

Clearly the library works with ANSI/ASCII chars. The nodave.pas unit works with PChar, which is PAnsiChar in Delphi versions up to D2007 and PWideChar above. You need to adjust the nodave.pas unit to handle that.

You might get away with replacing all PChar with PAnsiChar, but I haven't inspected it more deeply.

edited Feb 8, 2024 at 11:54

answered Feb 8, 2024 at 11:27

Uwe Raabe

48.6k3 gold badges94 silver badges142 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

David Heffernan Over a year ago

Clearly??? I mean we can see it's an 8 bit encoding but we don't know more than that. Could be UTF-8.

Uwe Raabe Over a year ago

From nodave.h: EXPORTSPEC char * DECL2 daveStrerror(int code); and S7 doesn't support UTF-8.

Uwe Raabe Over a year ago

In addition, all available error messages are plain ASCII.

MattiTheMaestro Over a year ago

Thanks @UweRaabe i replaced all PChar with PAnsiChar and it works.

Collectives™ on Stack Overflow

How to handle libnodave error message with Delphi?

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related