Adobe ExtendScript ExternalObject on 64 bit windows - adobe-indesign

Question

I'm trying to create an ExtendScript DLL library to load with the ExternalObject function.
It works great with InDesign versions that are 32 bit. However on a 64 bit version of InDesign CC on Windows it fails to load.
Setting ExternalObject.log = true only results in "ExtObj: load error!" message.
I'm trying to even get the sample projects "BasicExternalObject" and "SampleLib" to run and can't get those running.
I'm running Visual Studio 2015 Community Edition.
Thanks in advance for any pointers.

Answer 1

I was able to resolve this. It was a combination of issues.
Make sure all included libraries are compiled with same compiler settings for library. I used multi-threaded static.
See item 1 - make sure you don't have any dependency issues that require installing VS 2015 run-time libraries.
Need to have a version of the DLL for x64. The ExtendScript code needs to detect that environment and load the proper version.
var isWin = (File.fs == "Windows");
var libFilename = (isWin) ? "HttpLib.dll" : "HttpLib.framework";
if (isWin && ($.os.indexOf("64") > 0)) {
// we're on a 64 bit OS - see if the program path is in the 64 bit path
if (app.filePath.fsName.indexOf("x86") == -1) { // looks like we're 64 bit then
libFilename = "HttpLib64.dll";
}
}
use ".fsName" before loading - it was failing on directories that had spaces in the path.
var libPath = File($.fileName).parent.fsName + "/" + libFilename;
var httpLib = new ExternalObject("lib:" + libPath);

Answer 2

In Visual Studio, you need to compile and build for x64 platforms. You can do this by going to the dropdown under Visual Studio's main menu bar and selecting x64.
Of course, you will need to make sure your project properties are setup correctly for x64 platform. You can do that by right-clicking your project name in the "Solution Explorer" panel and then clicking on "Properties..." When the dialog comes up, make sure the dropdown at the top is set to x64.