了解gnu makefile声明

Question

下面的声明是什么意思。更具体地说''P'部分。 如何读取gnu makefile中的类似声明。

BUILD_TOOL   = ${toolname:P} 

Answer 1

这是一个BSD make特点：

:P The path of the node which has the same name as the variable is the value. If no such node exists or its path is null, then the name of the variable is used. In order for this modifier to work, the name (node) must at least have appeared on the rhs of a dependency.

没有什么类似于GNU做;你必须直接设置变量并在两个地方使用它（目标和变量等）