理解gnu makefile声明

Question

以下声明是什么意思。更具体地说''P'部分。 我如何在gnu makefile中读取类似的声明。

BUILD_TOOL         = ${toolname:P}

Answer 1

这是BSD make功能：

  

: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.

与GNU make没有任何相似之处;你必须直接设置变量并在两个地方（目标和变量等）使用它。