Question

我的makefile包含以下代码：

 .PHONY: $(PROJECTDIR)/projectroot
 $(PROJECTDIR)/projectroot:
if [ -f $(@)/etc/release ]; then \
         #$(RELEASE_VERSION) will have value something like 00.01.02.03
     IFS=. read major minor micro build <<<"${RELEASE_VERSION}" \
         echo major=${major} > $(@)/etc/release \
         echo major=${minor} >> $(@)/etc/release; \
         echo major=${micro} >> $(@)/etc/release; \
         echo major=${build} >> $(@)/etc/release; \
fi

我期待$（@）/ etc / release获得如下内容：

 major=00
 minor=01
 micro=02
 build=03

我需要替换IFS =。在gnu make中有一些相同的命令，你能帮帮我一下吗？感谢。

Answer 1

问题在于您将值读入名为major，minor等的shell变量中，但随后您将使用相同的名称打印Make变量。 shell无法设置Make变量。

要修复现有代码，您需要将$个字符重复为$$，以便向shell输出$，这将解释它们（您也说“主要” “每一次，都缺少一些分号”：

     IFS=. read major minor micro build <<<"${RELEASE_VERSION}" ; \
     echo major=$${major} > $(@)/etc/release ;\
     echo minor=$${minor} >> $(@)/etc/release; \
     echo micro=$${micro} >> $(@)/etc/release; \
     echo build=$${build} >> $(@)/etc/release; \

但要在内部进行，您可以使用subst and word函数：

REL_WORDS := $(subst ., ,${RELEASE_VERSION})
...
     echo major=$(word 1,${REL_WORDS}) >  $(@)/etc/release ;\
     echo minor=$(word 2,${REL_WORDS}) >> $(@)/etc/release ;\
     echo micro=$(word 3,${REL_WORDS}) >> $(@)/etc/release ;\
     echo build=$(word 4,${REL_WORDS}) >> $(@)/etc/release ;\

Answer 2

.PHONY: $(PROJECTDIR)/projectroot
$(PROJECTDIR)/projectroot: $(PROJECTDIR)/projectroot/etc/release
$(PROJECTDIR)/projectroot/etc/release:
    echo "${RELEASE_VERSION}" | \
    sed 's/^/major=/; s/\./\nminor=/; s/\./\nmicro=/; s/\./\nbuild=/' >$@

将依赖项添加到发布文件中。

使用分隔符在gnu make中拆分字符串

2 个答案: