[RuntimeError: unreachable] Retrieving from async function in C++

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fidel espanto

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1:46 AM (3 hours ago) 1:46 AM

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I'm trying to call an async function, 'isConfigSupported' from WebCodecs API.

Here is what I did in C++,

   val VideoDecoder = val::global("VideoDecoder");
   ConfigCodec* config = new ConfigCodec(); // some struct
   config->codec = "vp8";
   config->codedWidth = 640;
   config->codedHeight = 480;

   val result = VideoDecoder.call<val>("isConfigSupported", config).await();
   
   if (result["supported"].as<bool>()) {
      EM_ASM(
         console.log("Codec is supported");
      );
   } else {
      EM_ASM(
         console.error("Codec is not supported");
      );
   }

I have compiled emcc with this additional option, '-O3 -sASYNCIFY' as stated in the documentation.

The result is 'Codec is supported', however, I get an error in the console logs,

wasmapi.wasm:0x1e79f Uncaught (in promise) RuntimeError: unreachable
at wasmapi.wasm:0x1e79f
at wasmapi.wasm:0x1ca34
at wasmapi.wasm:0x118be
at ret.<computed> (wasmapi.js:1:87071)
at Object.doRewind (wasmapi.js:1:88672)
at wasmapi.js:1:89246