Re: Bug#187391: libc0.3-dev: weirdness with sockaddr_un

[GOTO Masanori]

At Thu, 3 Apr 2003 03:42:11 +0200,
Robert Millan wrote:
> the following code seems to be compliant with the Glibc documentation
> referred to sockaddr_un, as it provides a char* as the second component
> of the struct:
> 
>   #include <sys/socket.h>
>   #include <sys/un.h>
>   main ()
>   {
>     sockaddr_un test = { AF_LOCAL, "" };
>   }
> 
> however, when built with g++ (and not with gcc) on GNU/Hurd, it reports
> mismatch errors:
> 
>   test.c: In function `int main()':
>   test.c:6: invalid conversion from `const char*' to `unsigned char'
d
> 
> which is strange that it expects a char when both the documentation
> and <sys/un.h> agree that it should be a char*.
> 
> the code in question compiles fine on GNU/Linux.

SUSv3 describes sockaddr_un has at least sun_family and sun_path.  The
definition of 4.4BSD adds sun_len.  Hurd uses the generic definition,
and other use the 4.4BSD's.  Historically, BSD (4.2?) does not have
sun_len member in struct sockaddr_un.  Nowadays BSD (after 4.3?) has
sockaddr_un.sun_len.

sockaddr_un can be variable length, so I think your program style
should be avoided.  I think it's appropriate to use the substitution
like test.sun_family=AF_LOCAL, or so. 

I don't think it's bug.  I would like to close your report, ok?

Regards,
-- gotom