[libvirt] Re: [PATCH] syntax-check: prohibit all new uses of gethostby* functions
On Thu, Dec 11, 2008 at 09:28:12AM -0500, R P Herrold wrote:
On Thu, 11 Dec 2008, Jim Meyering wrote:
>Good point.
>Yet another reason not to use gethostbyname.
>I think it's time to make the prohibition official.
I sure hope the Cygwin 1.7, which just released yesterday to
formal beta trial, and brings in getaddrinfo() for my win 2000
porting box, _works_ -- perhaps deprecate it for a while first
(understanding it is stated as 'prohibit all new uses ...')?
We use GNULIB which provides compatability for broken/incomplete
OS like cygwin
>+# Not only do they fail to deal well with ipv6, but the
gethostby*
>+# functions are also not thread-safe.
I think you mean to say here that the implementation you are
encountering is not thread safe
POSIX leaves thread safety undefined, which is just as bad as marking
it explicitly unsafe.
"The functions gethostbyname() and gethostbyaddr() may return pointers
to static data, which may be overwritten by later calls. "
No code can use this function and expect to be safe when using threads.
Even on an OS where its currently safe, there's no guarentee it'll stay
safe in the future
Furthermore they're explicitly deprecated
"POSIX.1-2001 marks gethostbyaddr() and gethostbyname() obsolescent.
See getaddrinfo(3), getnameinfo(3), gai_strerror(3)."
Daniel
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