libcef编译使用--使用VS2015

1.背景
现在好多客户端程序都内嵌浏览器，有的用于实现界面，有的用于实现一些特殊功能，比如网易云音乐，QQ客户端，微信桌面客户端等。如果要内嵌浏览器，传统的方法是加入自带的IE webbrowser activex控件，但是IE对html5标准的支持不是很好，无法完成一些最新的功能。此时webkit就是最好的选择，可是webkit是一个很复杂的工程，编译也非常麻烦。好在有人替我们完成这个工作。有个叫libcef的库，实现了对webkit的封装，我们只需要直接调用就可以了，从而往我们的程序嵌入webkit浏览器，实现我们需要的功能。上面说到的那三个软件都用到了libcef这个库，在这些程序的安装目录下我们可以看到libcef.dll，libEGL.dll等dll文件。

2.生成VS工程文件
从https://cefbuilds.com/下载预编译好的二进制包，我下载的是cef_binary_3.2526.1346.g1f86d24_windows32.7z，2526分支的32位版本。然后解压到本地，比如我的是D:\SDK\cef。虽然需要的dll以及两个lib文件已经帮我们编译好了，但此时libcef还不能直接使用，因为我们还需要libcef_dll_wrapper.lib这个文件，而这个需要我们自己编译，如果没有这个的话，我们运行里面的cefsimple:

// Copyright (c) 2013 The Chromium Embedded Framework Authors. All rights
// reserved. Use of this source code is governed by a BSD-style license that
// can be found in the LICENSE file.

#include <windows.h>

#include "cefsimple/simple_app.h"
#include "include/cef_sandbox_win.h"


// When generating projects with CMake the CEF_USE_SANDBOX value will be defined
// automatically if using the required compiler version. Pass -DUSE_SANDBOX=OFF
// to the CMake command-line to disable use of the sandbox.
// Uncomment this line to manually enable sandbox support.
// #define CEF_USE_SANDBOX 1

#if defined(CEF_USE_SANDBOX)
// The cef_sandbox.lib static library is currently built with VS2013. It may not
// link successfully with other VS versions.
#pragma comment(lib, "cef_sandbox.lib")
#endif


// Entry point function for all processes.
int APIENTRY wWinMain(HINSTANCE hInstance,
                      HINSTANCE hPrevInstance,
                      LPTSTR    lpCmdLine,
                      int       nCmdShow) {
  UNREFERENCED_PARAMETER(hPrevInstance);
  UNREFERENCED_PARAMETER(lpCmdLine);

  // Enable High-DPI support on Windows 7 or newer.
  CefEnableHighDPISupport();

  void* sandbox_info = NULL;

#if defined(CEF_USE_SANDBOX)
  // Manage the life span of the sandbox information object. This is necessary
  // for sandbox support on Windows. See cef_sandbox_win.h for complete details.
  CefScopedSandboxInfo scoped_sandbox;
  sandbox_info = scoped_sandbox.sandbox_info();
#endif

  // Provide CEF with command-line arguments.
  CefMainArgs main_args(hInstance);

  // SimpleApp implements application-level callbacks. It will create the first
  // browser instance in OnContextInitialized() after CEF has initialized.
  CefRefPtr<SimpleApp> app(new SimpleApp);

  // CEF applications have multiple sub-processes (render, plugin, GPU, etc)
  // that share the same executable. This function checks the command-line and,
  // if this is a sub-process, executes the appropriate logic.
  int exit_code = CefExecuteProcess(main_args, app.get(), sandbox_info);
  if (exit_code >= 0) {
    // The sub-process has completed so return here.
    return exit_code;
  }

  // Specify CEF global settings here.
  CefSettings settings;

#if !defined(CEF_USE_SANDBOX)
  settings.no_sandbox = true;
#endif

  // Initialize CEF.
  CefInitialize(main_args, settings, app.get(), sandbox_info);

  // Run the CEF message loop. This will block until CefQuitMessageLoop() is
  // called.
  CefRunMessageLoop();

  // Shut down CEF.
  CefShutdown();

  return 0;
}

// reserved. Use of this source code is governed by a BSD-style license that

// can be found in the LICENSE file.

#include <windows.h>

#include "cefsimple/simple_app.h"

#include "include/cef_sandbox_win.h"

// When generating projects with CMake the CEF_USE_SANDBOX value will be defined

// automatically if using the required compiler version. Pass -DUSE_SANDBOX=OFF

// to the CMake command-line to disable use of the sandbox.

// Uncomment this line to manually enable sandbox support.

// #define CEF_USE_SANDBOX 1

#if defined(CEF_USE_SANDBOX)

// The cef_sandbox.lib static library is currently built with VS2013. It may not

// link successfully with other VS versions.

#pragma comment(lib, "cef_sandbox.lib")

#endif

// Entry point function for all processes.

int APIENTRY wWinMain(HINSTANCE hInstance,

HINSTANCE hPrevInstance,

LPTSTR lpCmdLine,

int nCmdShow) {

UNREFERENCED_PARAMETER(hPrevInstance);

UNREFERENCED_PARAMETER(lpCmdLine);

// Enable High-DPI support on Windows 7 or newer.

CefEnableHighDPISupport();

void* sandbox_info = NULL;

#if defined(CEF_USE_SANDBOX)

// Manage the life span of the sandbox information object. This is necessary

// for sandbox support on Windows. See cef_sandbox_win.h for complete details.

CefScopedSandboxInfo scoped_sandbox;

sandbox_info = scoped_sandbox.sandbox_info();

#endif

// Provide CEF with command-line arguments.

CefMainArgs main_args(hInstance);

// SimpleApp implements application-level callbacks. It will create the first

// browser instance in OnContextInitialized() after CEF has initialized.

CefRefPtr<SimpleApp> app(new SimpleApp);

// CEF applications have multiple sub-processes (render, plugin, GPU, etc)

// that share the same executable. This function checks the command-line and,

// if this is a sub-process, executes the appropriate logic.

int exit_code = CefExecuteProcess(main_args, app.get(), sandbox_info);

if (exit_code >= 0) {

// The sub-process has completed so return here.

return exit_code;

}

// Specify CEF global settings here.

CefSettings settings;

#if !defined(CEF_USE_SANDBOX)

settings.no_sandbox = true;

#endif

// Initialize CEF.

CefInitialize(main_args, settings, app.get(), sandbox_info);

// Run the CEF message loop. This will block until CefQuitMessageLoop() is

// called.

CefRunMessageLoop();

// Shut down CEF.

CefShutdown();

return 0;

}

会报如下错误：

Severity	Code	Description	Project	File	Line
Error	LNK2019	unresolved external symbol "int __cdecl CefExecuteProcess(class CefMainArgs const &,class CefRefPtr<class CefApp>,void *)" (?CefExecuteProcess@@YAHABVCefMainArgs@@V?$CefRefPtr@VCefApp@@@@PAX@Z) referenced in function _wWinMain@16	cefsample	D:\vs2015\cefsample\cefsample\Source.obj	1
Error	LNK2019	unresolved external symbol "bool __cdecl CefInitialize(class CefMainArgs const &,class CefStructBase<struct CefSettingsTraits> const &,class CefRefPtr<class CefApp>,void *)" (?CefInitialize@@YA_NABVCefMainArgs@@ABV?$CefStructBase@UCefSettingsTraits@@@@V?$CefRefPtr@VCefApp@@@@PAX@Z) referenced in function _wWinMain@16	cefsample	D:\vs2015\cefsample\cefsample\Source.obj	1
Error	LNK2019	unresolved external symbol "void __cdecl CefShutdown(void)" (?CefShutdown@@YAXXZ) referenced in function _wWinMain@16	cefsample	D:\vs2015\cefsample\cefsample\Source.obj	1
Error	LNK2019	unresolved external symbol "void __cdecl CefRunMessageLoop(void)" (?CefRunMessageLoop@@YAXXZ) referenced in function _wWinMain@16	cefsample	D:\vs2015\cefsample\cefsample\Source.obj	1
Error	LNK2019	unresolved external symbol "void __cdecl CefEnableHighDPISupport(void)" (?CefEnableHighDPISupport@@YAXXZ) referenced in function _wWinMain@16	cefsample	D:\vs2015\cefsample\cefsample\Source.obj	1
Error	LNK2019	unresolved external symbol "public: __thiscall SimpleApp::SimpleApp(void)" (??0SimpleApp@@QAE@XZ) referenced in function _wWinMain@16	cefsample	D:\vs2015\cefsample\cefsample\Source.obj	1
Error	LNK1120	6 unresolved externals	cefsample	D:\vs2015\cefsample\Debug\cefsample.exe	1

Severity Code Description Project File Line

Error LNK2019 unresolved external symbol "int __cdecl CefExecuteProcess(class CefMainArgs const &,class CefRefPtr<class CefApp>,void *)" (?CefExecuteProcess@@YAHABVCefMainArgs@@V?$CefRefPtr@VCefApp@@@@PAX@Z) referenced in function _wWinMain@16 cefsample D:\vs2015\cefsample\cefsample\Source.obj 1

Error LNK2019 unresolved external symbol "bool __cdecl CefInitialize(class CefMainArgs const &,class CefStructBase<struct CefSettingsTraits> const &,class CefRefPtr<class CefApp>,void *)" (?CefInitialize@@YA_NABVCefMainArgs@@ABV?$CefStructBase@UCefSettingsTraits@@@@V?$CefRefPtr@VCefApp@@@@PAX@Z) referenced in function _wWinMain@16 cefsample D:\vs2015\cefsample\cefsample\Source.obj 1

Error LNK2019 unresolved external symbol "void __cdecl CefShutdown(void)" (?CefShutdown@@YAXXZ) referenced in function _wWinMain@16 cefsample D:\vs2015\cefsample\cefsample\Source.obj 1

Error LNK2019 unresolved external symbol "void __cdecl CefRunMessageLoop(void)" (?CefRunMessageLoop@@YAXXZ) referenced in function _wWinMain@16 cefsample D:\vs2015\cefsample\cefsample\Source.obj 1

Error LNK2019 unresolved external symbol "void __cdecl CefEnableHighDPISupport(void)" (?CefEnableHighDPISupport@@YAXXZ) referenced in function _wWinMain@16 cefsample D:\vs2015\cefsample\cefsample\Source.obj 1

Error LNK2019 unresolved external symbol "public: __thiscall SimpleApp::SimpleApp(void)" (??0SimpleApp@@QAE@XZ) referenced in function _wWinMain@16 cefsample D:\vs2015\cefsample\cefsample\Source.obj 1

Error LNK1120 6 unresolved externals cefsample D:\vs2015\cefsample\Debug\cefsample.exe 1

都是些 referenced in function _wWinMain@16的错误。
要编译libcef_dll_wrapper.lib文件，需要我们去生成VS工程文件，然后用VS打开编译。此时我们需要用到cmake软件。如下图所示打开cmake软件，设置代码目录以及工程文件生成目录：
cmake libcef

接着点击Configure，选择编译器，我用的是默认VS2015自带的：
cmake libcef

然后点击Generate即在cef目录下生成VS工程文件：
cmake libcef

如下图，目录下已经生成了cef.sln解决方案文件，此时我们打开cef.sln文件
cmake libcef

可以看到该解决方案下有5个工程：
cmake libcef

编译libcef_dll_wrapper工程即可得到libcef_dll_wrapper.lib文件，然后我们编译运行示例工程cefclient，即可看到一个简单的浏览器，很简单吧。
libcef demo

本作品采用知识共享署名-非商业性使用-禁止演绎 4.0 国际许可协议进行许可

文章评论

骑驴

觉得libcef前景怎么样，和electron有对比性吗？

2016年9月5日

Jianchihu

@骑驴 electron不了解

2016年9月6日

回复
- 骑驴
  
  @Jianchihu 这几天稍微了解了一下，libcef不太稳定。electron易用性较高。
  
  2016年9月8日
  
  回复
  - Jianchihu
    
    @骑驴 libcef这么多大公司都在用，不可能不稳定吧。
    
    2016年9月10日
    
    回复