GNU make manual 翻译(五十八)

最新推荐文章于 2025-09-12 18:45:12 发布

weixin_34314962

最新推荐文章于 2025-09-12 18:45:12 发布

阅读量56

点赞数

文章标签：操作系统

深入探讨变量定义和赋值的解析过程，包括立即赋值、递延赋值及特殊操作符处理。

继续翻译

Variable Assignment                        
-------------------                        
                        
Variable definitions are parsed as follows:                        
                        
     IMMEDIATE = DEFERRED                        
     IMMEDIATE ?= DEFERRED                        
     IMMEDIATE := IMMEDIATE                        
     IMMEDIATE += DEFERRED or IMMEDIATE                        
                        
     define IMMEDIATE                        
       DEFERRED                        
     endef                        
                        
     define IMMEDIATE =                        
       DEFERRED                        
     endef                        
                        
     define IMMEDIATE ?=                        
       DEFERRED                        
     endef                        
                        
     define IMMEDIATE :=                        
       IMMEDIATE                        
     endef                        
                        
     define IMMEDIATE +=                        
       DEFERRED or IMMEDIATE                        
     endef                        
                        
   For the append operator, `+=', the right-hand side is considered 
immediate if the variable was previously set as a simple variable 
(`:='), and deferred otherwise.

变量定义被如下解析：

IMMEDIATE = DEFERRED
IMMEDIATE ?= DEFERRED
IMMEDIATE := IMMEDIATE
IMMEDIATE += DEFERRED or IMMEDIATE

define IMMEDIATE
DEFERRED
endef

define IMMEDIATE =
DEFERRED
endef

define IMMEDIATE ?=
DEFERRED
endef

define IMMEDIATE :=
IMMEDIATE
endef

define IMMEDIATE +=
DEFERRED or IMMEDIATE
endef

For the append operator, `+=', the right-hand side is considered
immediate if the variable was previously set as a simple variable
(`:='), and deferred otherwise.

对于连接符号 +=，如果变量已经被定义为一个简单变量(:=)，那么右手边就被认为是立即性的，

否则就是推迟性的。

后文待续