Emscripten: Uncaught UnboundTypeError: Cannot call XXX due to unbound types: PKc

[yss123yss]

Hi,
maybe a stupid question :)
I wrote the test .cpp file, and try to make it tun in the javascript. This error occurred.
here are the test code.

test.h

include

include

include

using namespace emscripten;
extern "C" {
int mmm(int aaa);
int hhh(const char* aaa);
}
EMSCRIPTEN_BINDINGS(my_value_example) {
function("mmm", &mmm);
function("hhh", &hhh, allow_raw_pointers());
}

test.cpp

include

using namespace std;
int mmm(int aaa){
return 123;
}

int hhh(const char* aaa){
return 34;
}

test.html

<script type='text/javascript'>
  **function sasa(){
    //alert("Hello");
    var mmmVal = Module.mmm(342);
    alert(mmmVal);
    var hhhVal = Module.hhh("sd");
    alert(hhhVal);
  }**
</script>
<script async type="text/javascript" src="test.js"></script>

so, the Module.mmm function can be conducted, but the Module.hhh function got this error.

i thought this is mainly related with the "allow_raw_pointers()" option. but still have no idea how to make it correct.
really appreciate.

[yss123yss]

ps:
if i write the cpp code as this:
int jjj(const std::string aaa);

   function("jjj", &jjj);

   int jjj(const std::string aaa){
    return 1234;
   }

that will be OK.

[AlexPerrot]

Hi,

This is because the char* type is not registered by embind. Using raw pointers directly is not always a good idea. If you want to be able to call your function with js string without changing your c interface, you can always use embind's optional_override :

#include <emscripten/bind.h>

using namespace emscripten;

int bla(const char* ptr) {
    return 42;
}

EMSCRIPTEN_BINDINGS(bla) {
    function("bla", optional_override(
                           [](const std::string s){
                                 return bla(s.c_str());
                              }));
}

This, way you can call bla("hello") from js, but still have the const char* C interface.

[yss123yss]

@AlexPerrot, Thanks a lot for your help :)

[cqq626]

@AlexPerrot
I want to use the pointer of a struct as a paramter of a function in class like:

#include <emscripten/bind.h>
using namespace emscripten;

typedef struct _RGEvent_t
{
    int status;
    //other property
}RGEvent_t;

class RGDataMgr
{
public:
    RGDataMgr(){};
    ~RGDataMgr(){};

    void setEvents(int eventCnt, RGEvent_t* events) {
      //some code here
      return ;
    }
};

EMSCRIPTEN_BINDINGS(my_module) {
  value_object<RGEvent_t>("RGEvent_t")
    .field("status", &RGEvent_t::status)
    ;

  class_<RGDataMgr>("RGDataMgr")
    .constructor<>()
    .function("setEvents", &RGDataMgr::setEvents, allow_raw_pointers())
    ;
}

And when I call the setEvents function at html, the same error 'UnboundTypeError: Cannot call RGDataMgr.setEvents due to unbound types: P10_RGEvent_t' occurred. I've read the optional_override documention here. Without more examples, I'm still confused.

[stale[bot]]

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