fun with sockaddr...

Andreas Bauer baueran at
Sun Sep 15 09:05:45 EST 2002

> For example:
> 	h1[0] = h2[0] = '\0';
> 	if (getnameinfo((struct sockaddr *)&ss[0],
> 	    ((struct sockaddr *)&ss[0])->sa_len, h1, sizeof(h1),
> 	    p, sizeof(p), niflag) != 0)
> 		return 0;
> As far as I can tell, sockaddr doesn't have a sa_len element (and the compiler 
> agrees). The man page for getnameinfo() doesn't help me much - it also uses 
> the sa_len approach.

I used this stuff a bit in Mailfilter and I believe sa_len returned the
size of the sockaddr_xyz struct.  Glibc used to have a macro called
SA_LEN(sa), but that's gone now, as far as I can tell.  So, you can
define your own along the lines of

#ifndef SA_LEN
#define SA_LEN(sa) sizeof(struct sockaddr_xyz)

You get the idea, I hope.


(o_  Andreas Bauer, baueran at,
//\  "Should've bought a Holden, Frank!" -- Ozzie in Bad Taste

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