Makefile中:=, =, ?=, += - Mon, Nov 7, 2022

Makefile中:=, =, ?=, +=的区别

:=

A := A
B := $(A)B
A := AA

B的值为AB

=

A = A
B = $(A)B
A = AA

B的值为AAB

?=

A = A
A ?= AA

A的值为A

A ?= AA

A的值为AA

+=

A = A
A += AA

A的值为AAA