嵌套Makefile问题解决一例

嵌套Makefile问题解决一例
先看一下目录结构

总控Makefile如下：
```
   1:  CFLAGS=-Wall
```
```
   2:  CC=gcc
```
```
   3:   
```
```
   4:   
```
```
   5:  SUBDIRS=server client
```
```
   6:   
```
```
   7:  export CFLAGS CC
```
```
   8:   
```
```
   9:   
```
```
  10:   
```
```
  11:  all:$(SUBDIRS)
```
```
  12:   
```
```
  13:  $(SUBDIRS):
```
```
  14:      make -C $@
```
```
  15:   
```
```
  16:   
```
```
  17:  clean:
```
```
  18:      $(RM) server/*.o  server/server 
```
```
  19:      $(RM) client/*.o client/client
```
```
  20:  .PHONY:clean 
```
另外两个Makefile分别如下：
```
   1:  server:server.o
```
```
   2:      $(CC) $(CFLAGS) $^ -o $@
```
```
   3:   
```
```
   4:  server.o:server.c
```
```
   5:      $(CC) $(CFLAGS) -c $^ -o $@
```
```
   1:  client:client.o
```
```
   2:      $(CC) $(CFLAGS) $^ -o $@
```
```
   3:   
```
```
   4:  client.o:client.c
```
```
   5:      $(CC) $(CFLAGS) -c $^ -o $@
```
当执行总控Makefile时，出现如下现象：

无法实现程序的编译。

解决方法：

方法一、将总控Makefile中的$(SUBDIRS)中的两个路径都声明为伪目标。
```
   1:  CFLAGS=-Wall
```
```
   2:  CC=gcc
```
```
   3:   
```
```
   4:   
```
```
   5:  SUBDIRS=server client
```
```
   6:   
```
```
   7:  export CFLAGS CC
```
```
   8:   
```
```
   9:   
```
```
  10:   
```
```
  11:  all:$(SUBDIRS)
```
```
  12:   
```
```
  13:  $(SUBDIRS):
```
```
  14:      make -C $@
```
```
  15:   
```
```
  16:   
```
```
  17:  clean:
```
```
  18:      $(RM) server/*.o  server/server 
```
```
  19:      $(RM) client/*.o client/client
```
```
  20:  .PHONY:clean server client 
```
再次指向make

方法二、将总控Makefile作如下修改
```
   1:  CFLAGS=-Wall
```
```
   2:  CC=gcc
```
```
   3:   
```
```
   4:   
```
```
   5:  SUBDIRS=server client
```
```
   6:   
```
```
   7:  export CFLAGS CC
```
```
   8:   
```
```
   9:   
```
```
  10:   
```
```
  11:  all:$(SUBDIRS)
```
```
  12:   
```
```
  13:  $(SUBDIRS):pp
```
```
  14:      make -C $@
```
```
  15:  pp:
```
```
  16:   
```
```
  17:  clean:
```
```
  18:      $(RM) server/*.o  server/server 
```
```
  19:      $(RM) client/*.o client/client
```
```
  20:  .PHONY:clean
```
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原文地址：https://www.cnblogs.com/pengdonglin137/p/2960210.html