string - 生成文件: contains string

Question

变量返回MINGW32_NT-5.1或CYGWIN_NT-5.1。(是的，末尾有点)

需要比较给定的 var 是否包含位于任意位置的 NT-5.1。

使用 cygwin 并希望与几乎任何 *nix 兼容。

Answer 1

findstring功能是您内心的渴望:

$(findstring find,in)

Searches in for an occurrence of find. If it occurs, the value is find; otherwise, the value is empty. You can use this function in a conditional to test for the presence of a specific substring in a given string. Thus, the two examples,

$(findstring a,a b c)
$(findstring a,b c)

produce the values "a" and "" (the empty string), respectively. See Testing Flags, for a practical application of findstring.

类似于:

ifneq (,$(findstring NT-5.1,$(VARIABLE)))
    # Found
else
    # Not found
endif

What is the comma here for ifneq (,$(...?

将其解析为 ifneq(A,B)，其中 A 是空字符串，B 是 $(findstring.. .)。这看起来很奇怪，因为您没有在 Makefile 中引用字符串。