makefile - 如何搜索 Makefile 字符串中的整个单词？

Question

我需要一种仅在子字符串是整个单词时才搜索子字符串的方法。

理想情况下，我想要一个函数(例如 findwstring())，这样两个示例
$(findwstring a, a b c)
$(findwstring a, 角度 b c)
应分别生成值“a”和“”(空字符串)。

我找不到任何东西here这可以帮助我。

Answer 1

$(filter a, a b c)

产生'a'。

$(filter a, angle b c)

产生''。

搜索字符串中的百分比 (%) 被视为通配符。

从您链接的文档中(实际上是findstring下面的函数)，粗体我的:

$(filter pattern…,text)

Returns all whitespace-separated words in text that do match any of the pattern words, removing any words that do not match. The patterns are written using ‘%’, just like the patterns used in the patsubst function above.

The filter function can be used to separate out different types of strings (such as file names) in a variable. For example:

sources := foo.c bar.c baz.s ugh.h
foo: $(sources)
        cc $(filter %.c %.s,$(sources)) -o foo

says that foo depends of foo.c, bar.c, baz.s and ugh.h but only foo.c, bar.c and baz.s should be specified in the command to the compiler.