SWI-Prolog -- API-function PL_chars_to

Availability:C-language interface function

bool PL_chars_to_term(const char *chars, term_t -t)

Parse the string chars and put the resulting Prolog term into t. chars may or may not be closed using a Prolog full-stop (i.e., a dot followed by a blank). Returns FALSE if a syntax error was encountered and TRUE after successful completion. In addition to returning FALSE, the exception-term is returned in t on a syntax error. See also term_to_atom/2.

The following example builds a goal term from a string and calls it.

int
call_chars(const char *goal)
{ fid_t fid = PL_open_foreign_frame();
  term_t g = PL_new_term_ref();
  BOOL rval;

  if ( PL_chars_to_term(goal, g) )
    rval = PL_call(goal, NULL);
  else
    rval = FALSE;

  PL_discard_foreign_frame(fid);
  return rval;
}
  ...
  call_chars("consult(load)");
  ...

PL_chars_to_term() is defined using PL_put_term_from_chars() which can deal with not null-terminated strings as well as strings using different encodings:

int
PL_chars_to_term(const char *s, term_t t)
{ return PL_put_term_from_chars(t, REP_ISO_LATIN_1, (size_t)-1, s);
}