why strong symbal not cover weak symbal?

[Carmelo AMOROSO]

On 02/11/2012 14.54, 风涯 wrote:
> first an example
> 
>  libmya.c
> [code]
>  #include<stdio.h>
>  void PrintA()
>  {
>    printf("A\n");
>  }
> 
>  __attribute__ ((weak))
>  void myfunc()
>  {
>    printf("myfunc in libmya\n");
>  }
>  [/code]
> 
> 
> libmyb.c
> [code]
>  #include<stdio.h>
>  void PrintB()
>  {
>    printf("B\n");
>  }
>  void myfunc()
>  {
>    printf("myfunc in libmyb\n");
>  }
>  [/code]
> 
> main.c
> 
> [code]
>  void main()
>  {
>    PrintA();
>    PrintB();
>    myfunc();
>  }
>  [/code]
> 
> 
> Makefile
> [code]
> 
> CC=gcc
> ALL:main
> main:main.c libmya.so libmyb.so
>         ${CC} main.c -L. -Wl,-rpath,. libmya.so libmyb.so -o main -g
> libmya.so:libmya.c
>         ${CC} libmya.c -shared -fPIC -o libmya.so
> libmyb.so:libmyb.c
>         ${CC} libmyb.c -shared -fPIC -o libmyb.so
> clean:
>         rm main *.so *.o *.s
> [/code]
> 
> the result is:
> A
> B
> myfunc in libmya
> 
> why the strong symbal int libmyb.so didn't cover the weak one in libmya.so?
> 
> I know it is becuase the _function dl_find_hash in the dl-hash.c do nothing
> with the weak symbal . But I think if there is a strong one,we should
> choose it rather than weak one.

And this is the correct behaviour, and the only one supported in uClibc.

glibc behaves similarly, except if you set LD_DYNAMIC_WEAK.

weak are meaningful only for static libraries, not shared.

See, for example: http://sourceware.org/bugzilla/show_bug.cgi?id=3946.

Regards,
Carmelo



> 
> sorry for my bad English...
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