Makefile GNU在隐式规则中删除目标？

如果我在GNU Make 3.81/RHEL5下运行以下Make文件：

all: A1B/C A1B/D A2B/C A2B/D

A%B/C A%B/D: E.%
        @echo "Creating '$@' from '$^' with stem '$*'"

E.1 E.2:
        @echo "Generate '$@'"

我得到以下输出：

Generate 'E.1'
Creating 'A1B/C' from 'E.1' with stem '1'
Generate 'E.2'
Creating 'A2B/C' from 'E.2' with stem '2'

为什么不生成A1B/D和A2B/D文件？ （我的testcase中不存在具有此类名称的文件）

如果我通过命令行指定目标，使状态为“无需执行”：

如果我将隐式规则复制到它们的目标中，它就会起作用：

all: A1B/C A1B/D A2B/C A2B/D

A%B/C: E.%
        @echo "Creating '$@' from '$^' with stem '$*'"

A%B/D: E.%
        @echo "Creating '$@' from '$^' with stem '$*'"

E.1 E.2:
        @echo "Generate '$@'"
Generate 'E.1'
Creating 'A1B/C' from 'E.1' with stem '1'
Creating 'A1B/D' from 'E.1' with stem '1'
Generate 'E.2'
Creating 'A2B/C' from 'E.2' with stem '2'
Creating 'A2B/D' from 'E.2' with stem '2'

根据文件规定，这不应造成影响

提前谢谢

---

Michael

你对文档中说没有区别的说法不太正确。如果您有一个具有多个目标的模式规则（您确实有），则

make

假定这两个目标都将在配方的一次执行中实现

从：

模式规则可能有多个目标。与普通规则不同的是，这并不像许多具有相同先决条件和配方的不同规则那样起作用。如果模式规则有多个目标，make知道规则的配方负责生成所有目标。配方只执行一次以生成所有目标

您可以为您的案例确认此行为：

$ make -r -d
GNU Make 3.81
Copyright (C) 2006  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

This program built for i386-apple-darwin11.3.0
Reading makefiles...
Reading makefile `Makefile'...
Updating makefiles....
 Considering target file `Makefile'.
  Looking for an implicit rule for `Makefile'.
  No implicit rule found for `Makefile'.
  Finished prerequisites of target file `Makefile'.
 No need to remake target `Makefile'.
Updating goal targets....
Considering target file `all'.
 File `all' does not exist.
 Looking for an implicit rule for `all'.
 No implicit rule found for `all'.
  Considering target file `A1B/C'.
   File `A1B/C' does not exist.
   Looking for an implicit rule for `A1B/C'.
   Trying pattern rule with stem `1'.
   Trying implicit prerequisite `E.1'.
   Found an implicit rule for `A1B/C'.
    Considering target file `E.1'.
     File `E.1' does not exist.
     Finished prerequisites of target file `E.1'.
    Must remake target `E.1'.
Putting child 0x7fcad3c08440 (E.1) PID 34127 on the chain.
Live child 0x7fcad3c08440 (E.1) PID 34127 
Generate 'E.1'
Reaping winning child 0x7fcad3c08440 PID 34127 
Removing child 0x7fcad3c08440 PID 34127 from chain.
    Successfully remade target file `E.1'.
   Finished prerequisites of target file `A1B/C'.
  Must remake target `A1B/C'.
Putting child 0x7fcad3c08710 (A1B/C) PID 34128 on the chain.
Live child 0x7fcad3c08710 (A1B/C) PID 34128 
Creating 'A1B/C' from 'E.1' with stem '1'
Reaping winning child 0x7fcad3c08710 PID 34128 
Removing child 0x7fcad3c08710 PID 34128 from chain.
  Successfully remade target file `A1B/C'.
  Considering target file `A1B/D'.
  File `A1B/D' was considered already.
  Considering target file `A2B/C'.
   File `A2B/C' does not exist.
   Looking for an implicit rule for `A2B/C'.
   Trying pattern rule with stem `2'.
   Trying implicit prerequisite `E.2'.
   Found an implicit rule for `A2B/C'.
    Considering target file `E.2'.
     File `E.2' does not exist.
     Finished prerequisites of target file `E.2'.
    Must remake target `E.2'.
Putting child 0x7fcad3c08cd0 (E.2) PID 34129 on the chain.
Live child 0x7fcad3c08cd0 (E.2) PID 34129 
Generate 'E.2'
Reaping winning child 0x7fcad3c08cd0 PID 34129 
Removing child 0x7fcad3c08cd0 PID 34129 from chain.
    Successfully remade target file `E.2'.
   Finished prerequisites of target file `A2B/C'.
  Must remake target `A2B/C'.
Putting child 0x7fcad3c08cd0 (A2B/C) PID 34130 on the chain.
Live child 0x7fcad3c08cd0 (A2B/C) PID 34130 
Creating 'A2B/C' from 'E.2' with stem '2'
Reaping winning child 0x7fcad3c08cd0 PID 34130 
Removing child 0x7fcad3c08cd0 PID 34130 from chain.
  Successfully remade target file `A2B/C'.
  Considering target file `A2B/D'.
  File `A2B/D' was considered already.
 Finished prerequisites of target file `all'.
Must remake target `all'.
Successfully remade target file `all'.

请注意以下几行：

File `A1B/D' was considered already.
File `A2B/D' was considered already.

---

您好，我同意这是一种4.10的“文档概述”；-）但是为什么下面的代码可以正常工作呢<代码>全部：A1B/CD A1B/EF A1B/C%A1B/E%:E.%@echo“从带有词干“$*”的“$^”创建“$@”E.D E.F:@echo“生成“$@”，因为不同的词干匹配；同样的原因，您当前的应用程序运行于

A1B/C

和

A2B/C

。很高兴提供帮助！欢迎来到stackoverflow。

File `A1B/D' was considered already.
File `A2B/D' was considered already.