12.4.12.2 Initiating a query from C
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  • Documentation
    • Reference manual
      • Foreign Language Interface
        • The Foreign Include File
          • Calling Prolog from C
            • Initiating a query from C
              • PL_open_query()
              • PL_next_solution()
              • PL_cut_query()
              • PL_close_query()
              • PL_current_query()
              • PL_query_engine()
              • PL_query_arguments()
              • PL_set_query_data()
              • PL_query_data()
              • PL_call_predicate()
              • PL_call()
    • Packages
Availability:C-language interface function
bool PL_call(term_t t, module_t m)
Call term t just like the Prolog predicate once/1. t is called in the module m, or in the context module if m == NULL. Returns TRUE if the call succeeds, FALSE otherwise. If the goal raises an exception the return value is FALSE and the exception term is available using PL_exception(0).230Up to version 9.1.11 the debugger was started and the exception was not propagated. Figure 7 shows an example to obtain the number of defined atoms.