vpath of makefile

luckydog1984

//目录结构

test/makefile
test/aa
test/bb/a.c

//a.c内容

#include <stdio.h> int main() {     printf("hello makefile\n");     return ( 0 ); }

//makefile

vpath %.c aa:bb files:a.o         gcc -o files a.o a.o:a.c        gcc -c a.c clean:         rm files.exe         rm `find ./ -name "*\.o" -depth`

当执行make时候报错：
$ make
gcc -c a.c
gcc: a.c: No such file or d
gcc: no input files
make: *** [a.o] Error 1

跟踪错误：
$ make --debug=v
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 i686-pc-cygwin
Reading makefiles...
Reading makefile `makefile'...
Updating goal targets....
Considering target file `files'.
File `files' does not exist.
  Considering target file `a.o'.
   File `a.o' does not exist.
    Considering target file `a.c'.
     Finished prerequisites of target file `a.c'.
    No need to remake target `a.c'; using VPATH name `bb/a.c'.
   Finished prerequisites of target file `a.o'.
  Must remake target `a.o'.
gcc -c a.c
gcc: a.c: No such file or directory
gcc: no input files
make: *** [a.o] Error 1

然后注释掉 a.o:a.c部分后正常

vpath %.c aa:bb files:a.o         gcc -o files a.o #a.o:a.c #       gcc -c a.c clean:         rm files.exe         rm `find ./ -name "*\.o" -depth`

或者注释掉vpath,将a.c拷贝到父目录也是正常的。

#vpath %.c aa:bb files:a.o         gcc -o files a.o a.o:a.c        gcc -c a.c clean:         rm files.exe         rm `find ./ -name "*\.o" -depth`

不是很清楚vpath到底做了什么？使得有这样的调试信息产生……
No need to remake target `a.c'; using VPATH name `bb/a.c'.

lgfang

1. 
   
2. a.o:a.c
   
3.         gcc -c $<
   

复制代码

luckydog1984

原帖由 lgfang 于 2008-9-28 17:38 发表

a.o:a.c
        gcc -c $<

确实，改成这样就对了。我是没把参考文档看完呢？还是应该记住这个事实。。。

lgfang

原帖由 luckydog1984 于 2008-10-7 11:54 发表


确实，改成这样就对了。我是没把参考文档看完呢？还是应该记住这个事实。。。

先记住这个事实，然后弄明白为什么这样改就对了。