Access violation occurred when attempting to initialize dawn.

[Block Micro]

The code is rather simple:

static void initDawn() {
  wgpu::InstanceDescriptor desc = {};
  desc.nextInChain = nullptr;
  instance = wgpu::CreateInstance(&desc);
}

int main() {
  ::initGLFW();
  ::initDawn();

}

However, it crashes with an access violation error. Here's the backtrace and exception message. Any idea?

[Block Micro]

other information:

the program is also linked with skia-m120 statically, with only graphite-dawn enabled.

 I used MSVC and linked with MSVCRT Release version statically

[Block Micro]

在2024年1月26日星期五 UTC+8 18:38:16<Block Micro> 写道：

[Corentin Wallez]

This is most likely caused by using libdawn_proc as the WebGPU implementation and not initializing the static proc table. Try linking against libwebgpu_dawn instead.

Dawn has multiple implementations of the WebGPU header's functions:

• An implementation that does validation and calls the GPU driver. (libdawn_native, accessed directly with libwebgpu_dawn, which is what you should use)
• A client-server implementation for use in Web browsers.
• A couple implementations that allow switching between the two above by storing the pointers to all the functions in a static variable and calling them (libdawn_proc). Of course if the static table is not initialized, it will be filled with zeroes, and cause a segfault. I'm 99% sure it is what happens here.

So the problem here is not in the code, but in the build files that should link to a different target. I'm not sure what you are using, but in general a CMakeLists.txt like this one should work: https://github.com/beaufortfrancois/webgpu-cross-platform-app/blob/main/CMakeLists.txt

Hope this helps,

Cheers,

Corentin

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[Block Micro]

Yes, I'm using CMake and my CMakeList.txt is literally the same as the example.

target_link_libraries(demo PUBLIC skia opengl32 glfw3 vulkan-1 webgpu_dawn webgpu_cpp webgpu_glfw)

[Corentin Wallez]

Then I'm not sure, it might be worth trying the demo I linked, and if it works, dig more into what could be different.

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[Block Micro]

Hmm, after some investigation, I found that it's true that I'm using  libdawn_proc instead of  libdawn_native, but how..?

[Block Micro]

I finally figured it out... It's skia. Skia has a copy of dawn static lib in skia.lib, so I got two skia and ran into the issue.

[Felix Don]

Hi there,

I'm also facing the same issue.

Can you elaborate more on the solution you found?

[Felix Don]

ok found the solution,
Just replace the order of compilation