Makefile 特殊字符的含义和使用

Question

以下字符在 Makefile 中的含义是什么？

$@, $? , $* , $< , $^

我看过一些解释，但我没有完全了解如何准确使用它。

Answer 1

使用模式和特殊变量

When wildcard % appears in the dependency list, it is replaced with 
the same string that was used to perform substitution in the target.

Inside actions we can use:  
    $@ to represent the full target name of the current target  
    $? returns the dependencies that are newer than the current target  
    $* returns the text that corresponds to % in the target     
    $< returns the name of the first dependency 
    $^ returns the names of all the dependencies with space as the delimiter

如需进一步说明，请参阅此 github 链接