Pl_Query_End(PL_RECOVER) but unrecoverable query

[Bowie Owens]

Hi everyone,

I am trying to use SWIG 1.3 to access the GNU Prolog 1.2.17 C API in
Java 1.4.2 on RedHat Linux 8.0. I have the following code:

               int x = gprolog.Mk_Variable();
               int c = gprolog.Find_Atom("write");
               int[] arg = { x };
               int res = gprolog.Pl_Query_Call(c, 1, arg);
               while (res == 1) {
                       System.out.println("found solution");
                       res = gprolog.Pl_Query_Next_Solution();
               }
               if (res == 2) {
                       System.out.println("exception!");
               } else {
                       System.out.println("fail");
               }
               gprolog.Pl_Query_End(gprolog.PL_RECOVER);

When I execute the code I get output indicating that a single solution
has been found but when the Pl_Query_End call is executed I get "Fatal
Error: Pl_Query_End(PL_RECOVER) but unrecoverable query". Any thoughts
on what is going wrong would be most appreciated.

I have tried this with GNU Prolog 1.2.16 and still get the same result.
I have essentially the same code working under Python. However, I may
have messed up the typemaps for Java <-> C.

--
Bowie Owens

CSIRO Mathematical & Information Sciences
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