linux - GNU make - 只依赖于文件存在而不是修改时间

Question

我想要一个 makefile，其中我有一个任务 a，它只能在文件 b 存在时运行，但如果 b 则不需要重新运行> 已更新。我该怎么做？

Answer 1

你想要一个 order-only prerequisite :

Occasionally, however, you have a situation where you want to impose a specific ordering on the rules to be invoked without forcing the target to be updated if one of those rules is executed. In that case, you want to define order-only prerequisites.

请注意，并非所有版本的 make 都支持这一点。