'Platform' is null ... ?

[James W]

I'm calling "Isolate->IdleNotification(100)" within an isolate scope (via "v8::Isolate::Scope ..."), and at some point when "V8::GetCurrentPlatform()->CallOnBackgroundThread(...)" is called within V8, "V8::GetCurrentPlatform()" returns NULL, and the whole thing dies a fatal death. Any ideas why the current platform might be null? Or rather, what should be done to make sure it isn't? All my javascript test scripts run perfectly - just the garbage collection fails when I try to force it using that call.  Should I be calling it outside an isolate scope (and locker).

[James W]

Addition details: I'm using Visual Studio 2013, and compiled the source, the resulting libraries of which I use with the V8.Net wrapper (on codeplex). I run the following code before triggering the idle notification call:

v8::Locker __lockScope(engine->Isolate());
v8::Isolate::Scope __isolateScope(engine->Isolate());
v8::HandleScope __handleScope(Isolate::GetCurrent());

I tried different combinations, and it seems only `v8::Locker __lockScope` is required, but the platform is still null;

v8::Platform* V8::GetCurrentPlatform() {   
DCHECK(platform_);   // <-- 'platform_' is NULL
return platform_; 
}

[Sven Panne]

You need to initialize the platform, see e.g. https://code.google.com/p/v8/source/browse/branches/bleeding_edge/samples/shell.cc#82. No fancy locking etc. involved here, the platform is internally just  a global variable. Not nice, but OK for now...

[Jochen Eisinger]

Note that you'll also need to link against the v8_libplatform library to make this work

best

-jochen

On Fri, Sep 5, 2014 at 9:23 AM, Sven Panne <sven...@chromium.org> wrote:

You need to initialize the platform, see e.g. https://code.google.com/p/v8/source/browse/branches/bleeding_edge/samples/shell.cc#82. No fancy locking etc. involved here, the platform is internally just  a global variable. Not nice, but OK for now...

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[James]

Why is this not shown in the Google embedders guide?

-jw

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[Louis Santillan]

The philosophy seems to be that the code is always the most up to date
Documentation of v8. So questions about API and usage are best
answered by reading v8.h [0], and d8.cc [1] and/or samples (shell.cc
[2], process.cc [3], and lineprocessor.cc [4]), and/or the files in
src/.

[0] (https://code.google.com/p/v8/source/browse/trunk/include/v8.h)
[1] (https://code.google.com/p/v8/source/browse/trunk/src/d8.cc)
[2] (https://code.google.com/p/v8/source/browse/trunk/samples/shell.cc)
[3] (https://code.google.com/p/v8/source/browse/trunk/samples/process.cc)
[4] (https://code.google.com/p/v8/source/browse/trunk/samples/lineprocessor.cc)

[James]

Ok, thanks.

-jw
(sent via iPhone)

[Jochen Eisinger]

Hey,

that's not true. API changes are documented here: http://bit.ly/v8-api-changes and there was an PSA about this change a few weeks ago and API changes are documented in the logs of each release.

However, if you chose to build from bleeding_edge or any other not yet released version, you're indeed on your own. And our public docs, of course, reflect the API of the latest stable version.

best

-jochen

[James]

Thanks - would be nice if this is more accessible from the V8 project page (https://code.google.com/p/v8/). I shouldn't have to hunt it down.

-jw

(sent via iPhone)

[James W]

I compiled V8 successfully, and included "libplatform.h" in my host code (in order to call "v8::platform::CreateDefaultPlatform()"). "libplatform.h" now complains "error C1083: Cannot open include file: '\include/v8-platform.h': No such file or directory ....\include\libplatform\libplatform.h".  I can see that "v8_libplatform.lib" exists in V8's 'lib' folder, but no dll in the dll output folder (the parent folder).  Is there supposed to be a DLL, or is it part of an existing one? Not sure how this is put together.

[Jochen Eisinger]

you need to add the v8 directory to your include paths (not v8/include - though having both is also fine).

And yes, you have to link against the .lib file, there is no dll support for v8_libplatform (yet)

best

-jochen