C++包管理工具之conan

C++常用的包管理工具有vcpkg，CPM，conan。本文主要记录Ubuntu下的cmake中使用conan的ffmpeg使用方法以及采坑。

安装完成：


 conan -v
#出现
Conan version 2.0.7

跟着官网的文档：https://docs.conan.io/2.0/tutorial/consuming_packages/build_simple_cmake_project.html 写一个conanfile.txt


[requires]
ffmpeg/5.1

[generators]
cmake


[settings]
compiler=g++

如果刚安装完conan，但未使用，先初始化一下： conan profile detect --force 出了警告


$ conan profile detect --force
Found gcc 7
gcc>=5, using the major as version
gcc C++ standard library: libstdc++11
Detected profile:
[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=gnu14
compiler.libcxx=libstdc++11
compiler.version=7
os=Linux

WARN: This profile is a guess of your environment, please check it.
WARN: The output of this command is not guaranteed to be stable and can change in future Conan versions.
WARN: Use your own profile files for stability.
Saving detected profile to ~/.conan2/profiles/default

直接install命令 conan install . --output-folder=build --build=missing 很不幸，报错了


$ conan install . --output-folder=build --build=missing

======== Input profiles ========
Profile host:
[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=gnu14
compiler.libcxx=libstdc++11
compiler.version=7
os=Linux

Profile build:
[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=gnu14
compiler.libcxx=libstdc++11
compiler.version=7
os=Linux

ERROR: <your project path>:
ConfigParser: Unrecognized field 'settings'

然后修改conanfile.txt，去掉settings


[requires]
ffmpeg/5.1

[generators]
cmake

再次 conan install . --output-folder=build --build=missing 很不幸，再次报错


Skipped binaries
    meson/1.0.0, ninja/1.11.1
vaapi/system: RUN: dpkg-query -W -f='${Status}' libva-dev | grep -q "ok installed"
dpkg-query: 没有找到与 libva-dev 相匹配的软件包

ERROR: vaapi/system: Error in system_requirements() method, line 38
        apt.install(["libva-dev"], update=True, check=True)
        ConanException: System requirements: 'libva-dev' are missing but can't install because tools.system.package_manager:mode is 'check'.Please update packages manually or set 'tools.system.package_manager:mode' to 'install' in the [conf] section of the profile, or in the command line using '-c tools.system.package_manager:mode=install'

方法一：尝试现在手动安装：


sudo apt update
sudo apt install libva-dev

经过多次实践，需要好几个包


sudo apt-get install libva-dev libvdpau-dev libx11-dev libx11-xcb-dev libfontenc-dev libice-dev libsm-dev libxau-dev libxaw7-dev libxcomposite-dev libxcursor-dev libxdamage-dev libxdmcp-dev libxext-dev libxfixes-dev libxi-dev libxinerama-dev libxkbfile-dev libxmu-dev libxmuu-dev libxpm-dev libxrandr-dev libxrender-dev libxres-dev libxss-dev libxt-dev libxtst-dev libxv-dev libxvmc-dev libxxf86vm-dev libxcb-render0-dev libxcb-render-util0-dev libxcb-xkb-dev libxcb-icccm4-dev libxcb-image0-dev libxcb-keysyms1-dev libxcb-randr0-dev libxcb-shape0-dev libxcb-sync-dev libxcb-xfixes0-dev libxcb-xinerama0-dev libxcb-dri3-dev uuid-dev libxcb-cursor-dev  libxcb-util-dev libxcb-util0-dev  -y

方法二（废案）：conan install加上参数 -c tools.system.package_manager:mode=install

即再执行conan install . --output-folder=build --build=missing -c tools.system.package_manager:mode=install

这里看起来有危险操作，尚未加sudo权限。


vaapi/system: System requirements:  already installed
vdpau/system: RUN: dpkg-query -W -f='${Status}' libvdpau-dev | grep -q "ok installed"
dpkg-query: 没有找到与 libvdpau-dev 相匹配的软件包

vdpau/system: RUN: apt-get update
正在读取软件包列表... 完成
E: 无法打开锁文件 /var/lib/apt/lists/lock - open (13: 权限不够)
E: 无法对目录 /var/lib/apt/lists/ 加锁
W: 用 unlink 删除文件 /var/cache/apt/pkgcache.bin 出错 - RemoveCaches (13: 权限不够)
W: 用 unlink 删除文件 /var/cache/apt/srcpkgcache.bin 出错 - RemoveCaches (13: 权限不够)

ERROR: vdpau/system: Error in system_requirements() method, line 38
        apt.install(["libvdpau-dev"], update=True, check=True)
        ConanException: Command 'apt-get update' failed