Using the full range of uint64_t across the language boundary

[Márton Marczell]

Hi,

Given this example code:

#include <iostream>

#include <emscripten.h>

#define MYINT64 uint64_t

extern "C" void EMSCRIPTEN_KEEPALIVE bar (MYINT64 n) {

    std::cout << "C++ called from JS: " << n << std::endl;

}

EM_JS(void, foo, (MYINT64 i), {

    console.log("JS", i, typeof(i));

    Module.ccall('bar', null, ['number'], [i]);

});

int main() {

    auto some = std::numeric_limits<MYINT64>::max();

    std::cout << "C++ " << some << std::endl;

    foo(some);

}

The code prints:

C++ 18446744073709551615

JS -1n bigint

C++ called from JS: 18446744073709551615

[Márton Marczell]

Why does the number become negative in JS and what would be required for this to work?

I did compile with -sWASM_BIGINT.