_malloc is not defined in Unity 2017 webGL Player

Question

Hi all,

I'm working on a webGL project and I have a function where I send a JSON array from an external javascript to the unity player. I followed the instructions in the Unity 5.6 manual using lengthBytesUTF8 and _malloc like so:

 //my_external_javascript.js
 
 var my_global_array = ["my", "array", "data"];
 
 function UnityGetMarkerArray()
 {
     var returnStr = JSON.stringify(my_global_array);
     var buffer = _malloc(lengthBytesUTF8(returnStr) + 1);
     writeStringToMemory(returnStr, buffer);
     return buffer;
 }

This worked great.

Then I upgraded to Unity 2017.

Now even though the manual entry is largely unchanged, when I run the same code I now get an error saying _malloc is not defined:

_malloc is not defined

I can see that now _malloc and lengthBytesUTF8 are no longer defined anywhere, and I can't seem to get them back.

Is this a bug in the newest version of 2017? Could anyone perhaps provide me with replacement functions so I can keep working? Thanks!!

Answer 1

After hunting around the minified built code I found that there is a temporary workaround, you need to prefix all the previously global Unity functions with "unityPlayerInstance.Module.", ie:

 function UnityGetMarkerArray() {

     var returnStr = JSON.stringify(my_global_array);
     return(UnityAllocateMemoryAndReturnBuffer(returnStr));
 }

 function UnityAllocateMemoryAndReturnBuffer(str)
 {
     if(typeof _malloc != "undefined" && typeof lengthBytesUTF8 != "undefined" && typeof writeStringToMemory != "undefined")
     {
         // The way the manual advises we do it
         var buffer = _malloc(lengthBytesUTF8(str) + 1);
         writeStringToMemory(str, buffer);
         return buffer;
     }
     else
     {
         // Workaround for Unity 2017
         var buffer = unityPlayerInstance.Module._malloc(unityPlayerInstance.Module.lengthBytesUTF8(str) + 1);
         unityPlayerInstance.Module.writeStringToMemory(str, buffer);
         return buffer;
     }
 }

_malloc is not defined in Unity 2017 webGL Player

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