在 makefile 中设置 GCC 路径

Question

Whenever I am building my package it uses /usr/bin/g++ (system compiler). I want to build my package with C++11 constructs. I have tried -std=c++11 option but with system compiler it says unrecognized option. I want to build my package from a different gcc compiler which will get downloaded as part of my package dependency.

So, how can I specify the location of gcc compiler in Makefile?

Answer 1

There are multiple ways to achieve what you are looking for:

1. Setting the environment variable CXX just for the process that will run make :

    $ CXX=/path-to-your-compiler/g++ make

2. Exporting the environment variable CXX in your shell:

    $ CXX=/path-to-your-compiler/g++ $ export CXX $ make

3. Setting CXX at make 's command-line:

    $ make CXX=/path-to-your-compiler/g++

4. Inside your makefile:

    CXX := /path-to-your-compiler/g++

Note that setting the variable at make 's command line overrides the other values, and variables set inside the makefile override the ones obtained from the environment (unless the command-line option -e or --environment-overrides is provided).

Inside your makefile, you can still override any value set by other means by using the override directive:

override CXX := /path-to-your-compiler/g++