On Sun, Feb 05, 2023 at 04:28:36PM +0100, Alejandro Colomar wrote: Regardless of the merits of the patch, let's not introduce typos: > +++ b/man3type/sockaddr.3type > @@ -120,6 +120,26 @@ .SH NOTES > .I <netinet/in.h> > and > .IR <sys/un.h> . > +.SH BUGS > +.I sockaddr_storage > +was designed back when strict aliasing wasn't a problem. > +Back then, > +one would define a variable of that type, > +and then access it as any of the other > +.IR sockaddr_ * > +types, > +depending on the value of the first member. > +This is Undefined Behavior. > +However, there is no way to use these APIs without invoking Unedfined Behavior, Undefined > +either in the user program or in libc, > +so it is still recommended to use this method. > +The only correct way to use different types in an API is through a union. > +However, > +that union must be implemented in the library, > +since the type must be shared between the library and user code, > +so libc should be fixed by implementing > +.I sockaddr_storage > +as a union. > .SH SEE ALSO > .BR accept (2), > .BR bind (2), Also, while I could raise the issue with the Austin Group on your behalf to get the POSIX wording improved, I think it would work better if you initiate a bug report rather than having me do it: https://www.austingroupbugs.net/main_page.php -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
