您如何使用mktemp在makefile中创建目录？

发布于 2025-01-26 17:09:26 字数 942 浏览 1 评论 0原文

这是一个制造费的代码，说明某人如何在makefile中使用mktemp

TEST=$(shell mktemp -d)
mktemp:
    echo $(TEST)
    touch $(TEST)/test.txt
    ls $(TEST)
    cat $(TEST)/test.txt
    rm -rf $(TEST)

这是一个示例，输出的示例

❯ make mktemp 
echo /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.tQI5EeyW
/var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.tQI5EeyW
touch /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.lVL3N8Rp/test.txt
ls /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.sBW9FzgD
cat /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.Ti53SWSw/test.txt
cat: /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.Ti53SWSw/test.txt: No such file or directory
make: *** [mktemp] Error 1

是期望cat/var/folders/62/wkysd_4n0w57ljl9ycfsd9ycfsd9cc0000 gn/tmp.tmp.tmp.tmp.ti53swswswst.test.test.test.test.test.test.test.test.teast.teast.test. >不会出错。

在这种情况下，如何使用MKTEMP？

原文

This is a Makefile piece of code of how someone may use mktemp in a Makefile

TEST=$(shell mktemp -d)
mktemp:
    echo $(TEST)
    touch $(TEST)/test.txt
    ls $(TEST)
    cat $(TEST)/test.txt
    rm -rf $(TEST)

This is an example output

❯ make mktemp 
echo /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.tQI5EeyW
/var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.tQI5EeyW
touch /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.lVL3N8Rp/test.txt
ls /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.sBW9FzgD
cat /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.Ti53SWSw/test.txt
cat: /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.Ti53SWSw/test.txt: No such file or directory
make: *** [mktemp] Error 1

The expectation is that cat /var/folders/62/wkysd_4n0w57ljl9ycfsd9cc0000gn/T/tmp.Ti53SWSw/test.txt would not error.

How can mktemp be used in this case?

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黄昏下泛黄的笔记 2025-02-02 17:09:26

此行：

TEST=$(shell mktemp -d)

将test变量的值设置为字符串$（shell mktemp -d）。它不会扩展该字符串（不运行shell命令），而只能将字符串保持在原样。

现在，每当您以后在makefile中使用该值时，它会进行扩展，这意味着mktemp再次运行，并且您获得了不同的值：

mktemp:
        echo $(TEST)
        touch $(TEST)/test.txt
        ls $(TEST)
        cat $(TEST)/test.txt
        rm -rf $(TEST)

您想使用

TEST := $(shell mktemp -d)

另外，您只需使用shell操作编写配方，而不使用任何制造功能，例如shell：

mktemp:
        TEST=$(mktemp -d) && \
        echo $TEST && \
        touch $TEST/test.txt && \
        ls $TEST && \
        cat $TEST/test.txt && \
        rm -rf $TEST

默认情况下，请注意配方的每条逻辑行都在单独的外壳中运行，因此为了拥有全部这些行在同一外壳中运行（因此它们可以访问相同的$ test变量），您需要使用BackSlash将它们组合到单个逻辑线中。

This line:

TEST=$(shell mktemp -d)

sets the value of the TEST variable to the string $(shell mktemp -d). It doesn't expand that string (doesn't run the shell command), it just keeps the string as-is.

Now, every time you use that value later in the makefile, it's expanded which means mktemp is run again, and you get a different value:

mktemp:
        echo $(TEST)
        touch $(TEST)/test.txt
        ls $(TEST)
        cat $(TEST)/test.txt
        rm -rf $(TEST)

You want to use immediate expansion when you assign the variable, so that it is expanded only one time when the makefile is parsed; use:

TEST := $(shell mktemp -d)

Alternatively you can just write the recipe using shell operations and not use any make functions like shell:

mktemp:
        TEST=$(mktemp -d) && \
        echo $TEST && \
        touch $TEST/test.txt && \
        ls $TEST && \
        cat $TEST/test.txt && \
        rm -rf $TEST

Note by default each logical line of a recipe is run in a separate shell, so in order to have all the lines run in the same shell (so they have access to the same $TEST variable) you need to use backslash to combine them into a single logical line.

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