[C++知识库]Vcpkg之Windows下C++开源库神器

为什么要用Vcpkg？

作为一个Win C++ 程序员，最大的痛苦就是经常要引入一些第三方库时如libyuv，libheif,libcurl,这种我们首先需要解决的问题就是如何获取一个编译好的库，其次这些库如何引入到工程也是个问题。有的时候为了编译一个库，配置各种环境可能就已经劝退了很多的人。
这时候无比羡慕python、node那种一条命令安装的优越，当然linux下可以通过 wget或yum来安装第三方库。这时候用隆重请出微软推出的vcpkg。瞬间让我们的开发体验翻倍。
vcpkg 官方连接
Vcpkg官方的说明是可帮助您在 Windows、 Linux 和 MacOS 上管理 C 和 C++ 库。我目前只在windows下进行了验证，开发效率瞬间提升。

Vcpkg优点

• 包会有缓存管理和版本管理，可以升级版本
• 会自动检验包的依赖关系
• 无缝集成到Visual Studio中，无需设置值库的头文件所在目录（仅针对VS开发）

1.Vcpkg 前置要求

• Windows 7以上
• Git
• Visual Studio 2015 Update 3

这个配置要求真的不高，还在win7下开发的大部分都是涉密企业，这种在线安装库的形式基本上也不可能。

2.安装使用Vcpkg

使用Git安装Vcpkg

在powshell中输入以下命令下载并安装vcpkg

> git clone https://github.com/microsoft/vcpkg
> .\vcpkg\bootstrap-vcpkg.bat

在环境变量中添加vcpkg

主要是便于我们后续在任意的路径下，直接使用vcpkg进行安装第三方库
以我为例：

1. vcpkg安装在了“E:\Git\vcpkg”
2. 在环境变量Path路径的最后一行添加
   

vcpkg安装库注意点

安装库的命令

#package_name 替换自己需要安装的即可
> vcpkg install package_name
#vcpkg install libyuv

vcpkg在Windows中默认编译并安装x86版本的库。 若要编译并安装x64版本限定

#安装64位
> vcpkg install package_name:x64-windows
> vcpkg install package_name:x64 --triplet=x64-windows
#安装32位
> vcpkg install package_name
> vcpkg install package_name:x86-windows
> vcpkg install package_name:x64 --triplet=x86-windows

会自动下载package对应的编译依赖库

安装前可以先进行搜索

> vcpkg search package_name

更多的命令可以通过vcpkg --help查看

> vcpkg --help
> Commands:
  vcpkg search [pat]              Search for packages available to be built
  vcpkg install <pkg>...          Install a package
  vcpkg remove <pkg>...           Uninstall a package
  vcpkg remove --outdated         Uninstall all out-of-date packages
  vcpkg list                      List installed packages
  vcpkg update                    Display list of packages for updating
  vcpkg upgrade                   Rebuild all outdated packages
  vcpkg x-history <pkg>           (Experimental) Shows the history of CONTROL versions of a package
  vcpkg hash <file> [alg]         Hash a file by specific algorithm, default SHA512
  vcpkg help topics               Display the list of help topics
  vcpkg help <topic>              Display help for a specific topic

  vcpkg integrate install         Make installed packages available user-wide. Requires admin
                                  privileges on first use
  vcpkg integrate remove          Remove user-wide integration
  vcpkg integrate project         Generate a referencing nuget package for individual VS project use
  vcpkg integrate powershell      Enable PowerShell tab-completion

  vcpkg export <pkg>... [opt]...  Exports a package
  vcpkg edit <pkg>                Open up a port for editing (uses %EDITOR%, default 'code')
  vcpkg create <pkg> <url> [archivename]
                                  Create a new package
  vcpkg x-init-registry <path>    Initializes a registry in the directory <path>
  vcpkg format-manifest --all     Formats all vcpkg.json files. Run this before committing to vcpkg.
  vcpkg owns <pat>                Search for files in installed packages
  vcpkg depend-info <pkg>...      Display a list of dependencies for packages
  vcpkg env                       Creates a clean shell environment for development or compiling
  vcpkg version                   Display version information
  vcpkg contact                   Display contact information to send feedback

Options:
  --triplet=<t>                   Specify the target architecture triplet. See 'vcpkg help triplet'
                                  (default: %VCPKG_DEFAULT_TRIPLET%)
  --host-triplet=<t>              Specify the host architecture triplet. See 'vcpkg help triplet'
                                  (default: %VCPKG_DEFAULT_HOST_TRIPLET%)
  --overlay-ports=<path>          Specify directories to be used when searching for ports
                                  (also: %VCPKG_OVERLAY_PORTS%)
  --overlay-triplets=<path>       Specify directories containing triplets files
                                  (also: %VCPKG_OVERLAY_TRIPLETS%)
  --binarysource=<path>           Add sources for binary caching. See 'vcpkg help binarycaching'
  --x-asset-sources=<path>        Add sources for asset caching. See 'vcpkg help assetcaching'
  --downloads-root=<path>         Specify the downloads root directory
                                  (default: %VCPKG_DOWNLOADS%)
  --vcpkg-root=<path>             Specify the vcpkg root directory
                                  (default: %VCPKG_ROOT%)
  --x-buildtrees-root=<path>      (Experimental) Specify the buildtrees root directory
  --x-install-root=<path>         (Experimental) Specify the install root directory
  --x-packages-root=<path>        (Experimental) Specify the packages root directory
  --x-json                        (Experimental) Request JSON output

  @response_file                  Specify a response file to provide additional parameters

vcpkg第三方库与CMake的结合

cmake -B build_folder -S . “-DCMAKE_TOOLCHAIN_FILE=[path to vcpkg]/scripts/buildsystems/vcpkg.cmake”

注意这里的CMake路径为vcpkg安装的CMake路径
以我为例:

安装在了“E:\Git\vcpkg”

则Vcpkg的cmake安装在了

E:\Git\vcpkg\downloads\tools\cmake-3.22.2-windows\cmake-3.22.2-windows-i386\bin

最终执行的命令为

E:\Git\vcpkg\downloads\tools\cmake-3.22.2-windows\cmake-3.22.2-windows-i386\bin\cmake -B ./build_2019 -G “Visual Studio 15 2017 Win64” -S . “-DCMAKE_TOOLCHAIN_FILE=E:\Git\vcpkg\scripts\buildsystems\vcpkg.cmake”

CMake中如何添加安装的库

这个真的钞机无敌简单，因为你在安装之后，Vcpkg就直接把命令给了你，少走十年弯路啊！！！

> vcpkg install jsoncpp:x64-windows
Computing installation plan...
The following packages will be built and installed:
    jsoncpp[core]:x64-windows -> 1.9.5
Detecting compiler hash for triplet "x64-windows"...
-- Automatically setting HTTP(S)_PROXY environment variables to "127.0.0.1:7890".
......省略
CMake Warning at scripts/cmake/vcpkg_copy_pdbs.cmake:44 (message):
  Could not find a matching pdb file for:

      E:/Git/vcpkg/packages/jsoncpp_x64-windows/bin/jsoncpp.dll
      E:/Git/vcpkg/packages/jsoncpp_x64-windows/debug/bin/jsoncpp.dll

Call Stack (most recent call first):
  ports/jsoncpp/portfile.cmake:30 (vcpkg_copy_pdbs)
  scripts/ports.cmake:146 (include)


-- Installing: E:/Git/vcpkg/packages/jsoncpp_x64-windows/share/jsoncpp/copyright
-- Performing post-build validation
-- Performing post-build validation done
Stored binary cache: 
......省略

jsoncpp provides CMake targets:
    # this is heuristically generated, and may not be correct
    #看到没？如何在CMake中添加已经直接把命令给你了！！！
    find_package(jsoncpp CONFIG REQUIRED)
    target_link_libraries(main PRIVATE jsoncpp_lib jsoncpp_object JsonCpp::JsonCpp)

总结

这一套组合拳下来，真的是让Windows下的C++ 开发一下子幸福感爆满