V8编译问题

Question

我正在尝试使用 Google 的 V8 JavaScript 引擎编译一个文件。我安装了 scons 并编译了 V8 引擎。但是，这就是问题所在，正如他们所说，我留在 V8 目录中，并使用以下代码创建一个名为 hello_world.cpp 的文件：

#include <v8.h>

using namespace v8;

    int main(int argc, char* argv[]) {

      // Create a stack-allocated handle scope.
      HandleScope handle_scope;

      // Create a new context.
      Persistent<Context> context = Context::New();

      // Enter the created context for compiling and
      // running the hello world script. 
      Context::Scope context_scope(context);

      // Create a string containing the JavaScript source code.
      Handle<String> source = String::New("'Hello' + ', World!'");

      // Compile the source code.
      Handle<Script> script = Script::Compile(source);

      // Run the script to get the result.
      Handle<Value> result = script->Run();

      // Dispose the persistent context.
      context.Dispose();

      // Convert the result to an ASCII string and print it.
      String::AsciiValue ascii(result);
      printf("%s\n", *ascii);
      return 0;
    }

然后我使用 gcc hello_world.cpp -o 进行编译libv8.a。但是，当我编译它时，我遇到了一些错误：

hello_world.cpp:1:16: error: v8.h: No such file or directory
hello_world.cpp:3: error: ‘v8’ is not a namespace-name
hello_world.cpp:3: error: expected namespace-name before ‘;’ token
hello_world.cpp: In function ‘int main(int, char**)’:
hello_world.cpp:8: error: ‘HandleScope’ was not declared in this scope
hello_world.cpp:8: error: expected `;' before ‘handle_scope’
hello_world.cpp:11: error: ‘Persistent’ was not declared in this scope
hello_world.cpp:11: error: ‘Context’ was not declared in this scope
hello_world.cpp:11: error: ‘context’ was not declared in this scope
hello_world.cpp:11: error: ‘Context’ is not a class or namespace
hello_world.cpp:15: error: ‘Context’ is not a class or namespace
hello_world.cpp:15: error: expected `;' before ‘context_scope’
hello_world.cpp:18: error: ‘Handle’ was not declared in this scope
hello_world.cpp:18: error: ‘String’ was not declared in this scope
hello_world.cpp:18: error: ‘source’ was not declared in this scope
hello_world.cpp:18: error: ‘String’ is not a class or namespace
hello_world.cpp:21: error: ‘Script’ was not declared in this scope
hello_world.cpp:21: error: ‘script’ was not declared in this scope
hello_world.cpp:21: error: ‘Script’ is not a class or namespace
hello_world.cpp:24: error: ‘Value’ was not declared in this scope
hello_world.cpp:24: error: ‘result’ was not declared in this scope
hello_world.cpp:30: error: ‘String’ is not a class or namespace
hello_world.cpp:30: error: expected `;' before ‘ascii’
hello_world.cpp:31: error: ‘ascii’ was not declared in this scope
hello_world.cpp:31: error: ‘printf’ was not declared in this scope

我不明白为什么它说 V8.h 未声明。我已经构建了它并且位于它的目录中，我猜如果我摆脱它，所有其他错误都会消失。有什么建议吗？

Answer 1

我只是相信你确实在顶级源目录中（并且由于我没有编译 v8，我只相信 libvp8.a 是在该顶级目录中创建的）：

% g++ -Iinclude hello_world.cpp -o hello_world libv8.a

1. 它说“v8.h”不是声明是因为该文件位于“include”目录内，并且预处理器无法凭空找到它。

2. 此外：您正在使用 C 编译器而不是 C++ 编译器编译 .cpp 文件。

3. 您使用的“-o”标志是错误的，因为它定义了链接二进制文件的名称，因此需要一个名称，您不希望输出二进制文件被命名为“libvp8.a”