Existance error only when calling through C API. UTF-8 characters.

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Apr 10, 2016, 4:23:14 PM4/10/16
to SWI-Prolog
Hey I could use some help tackling this issue.
I was given a prolog source file and tasked with querying it through A C++ program.
The file is UTF-8 encoded.

When running swipl in the terminal i do the following:
B = [ajaleht].
Everything works as expected.

Through the C API however, I get the following error:
Prolog query failed: Failure to generate solution: error(existence_error(procedure,s??nad/2),context(system:call/1,_G42))
The problem goes away, if i remove the 'õ' character.

querying current_prolog_flag(encoding,X) returns X = 'utf8'.

The code i'm using to query in c++ can be found here:

take a look at Query::Impl::open()

Really hit the wall with this problem, any help is greatly appreciated.


Jan Wielemaker

Apr 11, 2016, 2:53:58 AM4/11/16
to kalmen...@gmail.com, SWI-Prolog
The C(++) interface has two string APIs. The one using char* is
always interpreted as ISO Latin 1. If you need something else
you must use the wchar_t* functions/methods and translate to
unicode yourself.

There is one exception, the PL_unify_chars() and variation functions.
They take a flag arg that may include REP_MB to indicate locale
specific multibyte encoding.

Cheers --- Jan
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