makefile - Makefile 规则定义中的分号

Question

我在 Makefile 中看到许多规则，如下所示:

$(PATH)/foo.inc:;
include $(PATH)/foo.inc

$(PATH)/bar.inc:;
include $(PATH)/bar.inc

规则定义末尾的分号是空操作还是具有特定含义？

Answer 1

带有目标先决条件的行上的分号是为此规则执行的第一个命令行，至少在 GNU make 中是这样。

从手册的第 5 章:

The commands of a rule consist of shell command lines to be executed one by one. Each command line must start with a tab, except that the first command line may be attached to the target-and-prerequisites line with a semicolon in between.

在您的情况下，由于分号后没有命令，因此它最终成为无操作。