GNU Make - 内部变量的赋值和改变

1. 赋值和显示

采用$(info $(variable_name))显示内部变量

eg:

FOO=bar
$(info $(FOO))

运行结果：

#: make

bar

 

2. 从命令行外部改变

BUILD_DEBUG := yes
.PHONY: all
all:
    @echo BUILD_DEBUG is $(BUILD_DEBUG)

运行结果:

#： make

BUILD_DEBUG is yes

#: make BUILD_DEBUG=no

BUILD_DEBUG is no