Calling javascript function in c++ with emscripten embind

Question

This question comes in two parts. What I want to do is to put most of my program logic in c++ classes and some view related function in js (like DOM manipulation and styling.) I use emscripten embind the classes and it works fine while I don't know how to interact with the js code (there are really limited resources on their tutorial.) I was thinking to pass a `val` object to the c++ class according to their tutorial (https://github.com/kripken/emscripten/wiki/Tutorial) The passing works just fine while the "call" function doesn't work. I got a compile time error. Here is the example I tried which they put on their tutorial: ``` #include <emscripten/val.h> using namespace emscripten; int main(){ val Math = val::global("Math"); Math.call("abs",-10); return 0; } ``` and I got the following errors: ``` error: no matching member function for call to 'call' Math.call("abs",-10); ~~~~^~~~ emscripten/1.5.6/system/include/emscripten/val.h:247:21: note: candidate template ignored: couldn't inf…

Accepted Answer

That's a common C++ problem. As a general rule, the following message should always make you double check in C++: ``` note: candidate template ignored: couldn't infer template argument 'ReturnValue' ReturnValue call(const char* name, Args&&... args) const ``` This mostly means that you tried to call a templated function but did not specify the necessary types. If you look at the signature (in `system/include/emscripten/val.h`): ``` template ReturnValue call(const char* name, Args&&... args) const ``` While it can infer `Args` quite fine, it has no idea, what `ReturnValue` might be. So calling this function should be done via e.g.: ``` Math.call("abs",-10); ```

Calling javascript function in c++ with emscripten embind

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