嵌入的问题(WebAssembly)

Question

所以我想把一个简单的c++文件编译成js，然后在web浏览器中运行它。我采取的步骤(在windows上)：

git clone https://github.com/emscripten-core/emsdk.git
cd emsdk
emsdk install latest
emsdk activate latest
emsdk_env.bat --global
emsdk update-tags
emcc -v

最后一条命令打印如下：

emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 1.39.15
clang version 11.0.0 "

然后我尝试在main.cpp文件中编译"hello world“，如下所示：

#include <iostream>
#include <emscripten.h>
int main()
{
    std::cout<< "hello world!" << std::endl;

    return 0;
}

然后在test文件夹中，我使用了以下命令：

em++ main.cpp -o 1.html

打印出来的：

cache:INFO: generating system library: libcompiler_rt.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libcompiler_rt.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libc-wasm.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libc-wasm.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libc++-noexcept.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libc++-noexcept.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libc++abi-noexcept.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libc++abi-noexcept.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libdlmalloc.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libdlmalloc.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libpthread_stub.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libpthread_stub.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libc_rt_wasm.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libc_rt_wasm.a" for subsequent builds)
cache:INFO:  - ok
cache:INFO: generating system library: libsockets.a... (this will be cached in "C:\Users\x\.emscripten_cache\wasm\libsockets.a" for subsequent builds)
cache:INFO:  - ok

作为输出，我得到了以下文件：1.html、1.js、1.wasm

当我打开1.html时，我看到了这些错误：

both async and sync fetching of the wasm failed
RuntimeError: abort(both async and sync fetching of the wasm failed) at jsStackTrace@file:///E:/emscripten/emsdk/test/1.js:1952:17
stackTrace@file:///E:/emscripten/emsdk/test/1.js:1969:16
abort@file:///E:/emscripten/emsdk/test/1.js:1728:44
getBinary@file:///E:/emscripten/emsdk/test/1.js:1800:10
getBinaryPromise/<@file:///E:/emscripten/emsdk/test/1.js:1822:13
getBinaryPromise@file:///E:/emscripten/emsdk/test/1.js:1821:10
instantiateArrayBuffer@file:///E:/emscripten/emsdk/test/1.js:1865:12
instantiateAsync@file:///E:/emscripten/emsdk/test/1.js:1892:14
createWasm@file:///E:/emscripten/emsdk/test/1.js:1908:3
@file:///E:/emscripten/emsdk/test/1.js:4990:11

我也在linux上尝试过，但出现了完全相同的错误。旧版本的emscripten SDK也不能工作。

有什么提示吗？

Answer 1

关于使用file://的问题，我认为你需要运行服务器并使用http://。请参阅：https://emscripten.org/docs/getting_started/FAQ.html#faq-local-webserver还有：https://emscripten.org/docs/compiling/Running-html-files-with-emrun.html

Answer 2

如果web服务器的目录中只有html文件夹，也可能发生此错误。关联的.wasm文件必须位于web服务器的文件夹中。

因此，对于hello_world示例，复制hello.html文件和hello.wasm文件。

如果在Chrome浏览器中测试，您可以打开开发人员工具面板并选择控制台选项卡。刷新页面并观察任何错误消息。