如何更改 Ubuntu 中的默认 GCC 编译器?
我已经在已经有 gcc/g++-4.4 的 ubuntu 11.04 上安装了 gcc-3.3/g++-3.3.所以在我的系统中，gcc-3.3 和 4.4 都可用.我可以根据需要调用两个编译器.如果我只是调用命令 gcc 然后 gcc-4.4 将被调用.要调用 gcc-3.3，我必须使用命令 gcc-3.3.
I have installed gcc-3.3/g++-3.3 on ubuntu 11.04 which already has gcc/g++-4.4. So in my system both gcc-3.3 and 4.4 are available. I am able to call both compilers as I want. If I just call the command gcc then gcc-4.4 will get called. To call gcc-3.3, I have to use the command gcc-3.3.
如何将默认编译器更改为 gcc-3.3?当我执行命令 gcc 时，它应该调用 gcc-3.3 而不是 gcc-4.4.
How can I change the default compiler as gcc-3.3? When I execute the command gcc it should call the gcc-3.3 and not gcc-4.4.
另外，如何将 make 文件中的变量 CXX 更改为 gcc-3.3?我希望更改系统中的一个公共全局位置，而不是更改所有 make 文件.
In addition, how can I change the variable CXX in a make file to gcc-3.3? I wish to change one common global place in the system instead of changing all make files.
正如@Tommy 建议的那样，你应该使用 update-alternatives.
它为一个系列的每个软件分配值，以便定义调用应用程序的顺序.
As @Tommy suggested, you should use update-alternatives.
It assigns values to every software of a family, so that it defines the order in which the applications will be called.
用于在系统上维护同一软件的不同版本.在您的情况下，您将能够使用 gcc 的多个偏角，并且一个偏角会受到青睐.
It is used to maintain different versions of the same software on a system. In your case, you will be able to use several declinations of gcc, and one will be favoured.
要确定 gcc 当前的优先级，请输入@tripleee 评论指出的命令:
To figure out the current priorities of gcc, type in the command pointed out by @tripleee's comment:
update-alternatives --query gcc
现在，请注意归因于 gcc-4.4 的优先级，因为您需要为 gcc-3.3 赋予更高的优先级.
要设置你的替代方案，你应该有这样的东西(假设你的 gcc 安装位于 /usr/bin/gcc-3.3 和 gcc-4.4的优先级小于50):
Now, note the priority attributed to gcc-4.4 because you'll need to give a higher one to gcc-3.3.
To set your alternatives, you should have something like this (assuming your gcc installation is located at /usr/bin/gcc-3.3, and gcc-4.4's priority is less than 50):
update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-3.3 50
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最后，您还可以使用update-alternatives的交互界面，轻松切换版本.输入 update-alternatives --config gcc 要求在安装的 gcc 版本中选择你想使用的 gcc 版本.
Finally, you can also use the interactive interface of update-alternatives to easily switch between versions. Type update-alternatives --config gcc to be asked to choose the gcc version you want to use among those installed.
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现在，要在系统范围内修复 CXX 环境变量，您需要将 @DipSwitch 指示的行放在您的 .bashrc 文件中(这将仅对您的用户应用更改，这样更安全)我的意见):
Now, to fix the CXX environment variable systemwide, you need to put the line indicated by @DipSwitch's in your .bashrc file (this will apply the change only for your user, which is safer in my opinion):
echo 'export CXX=/usr/bin/gcc-3.3' >> ~/.bashrc