Question

在我的makefile中，我想从...中更改搜索目录列表

DIRS := ../project ../project/include ../project/src

类似以下内容...

INCLUDES := -I"../project" -I"../project/include" -I"../project/src"

我尝试在makefile中使用以下命令...

INCLUDES := $(patsubst %,-I"%",$(DIRS))

当makefile输出列表时，它不包含引号...

INCLUDES = -I../project -I../project/include -I../project/src

但是，当调用编译器时，makefile使用以下行...

g++ ... -I"../project" -I"../project/include" -I"../project/src"

我不明白。他们为什么不同？

Answer 1

你正确地做到了。它是由Makefile配方调用的shell，使引号消失。考虑一下Makefile：

DIRS     := ../project ../project/include ../project/src
INCLUDES := $(patsubst %,-I"%",$(DIRS))

$(info $(INCLUDES))

all:
        @echo $(INCLUDES)

make all返回：

-I"../project" -I"../project/include" -I"../project/src"
-I../project -I../project/include -I../project/src

如您所见，patsubst文本功能很好地完成了它的工作由于外壳的可变扩展，报价已经消失为了保留它们，你应该尝试转义它们：

INCLUDES := $(patsubst %,-I\"%\",$(DIRS))

在这种情况下，make all输出：

-I\"../project\" -I\"../project/include\" -I\"../project/src\"
-I"../project" -I"../project/include" -I"../project/src"