瞭解gnu makefile聲明

Question

下面的聲明是什麼意思。更具體地說''P'部分。 如何讀取gnu makefile中的類似聲明。

BUILD_TOOL   = ${toolname:P} 

Answer 1

這是一個BSD make特點：

: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.

沒有什麼類似於GNU做;你必須直接設置變量並在兩個地方使用它（目標和變量等）