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Date: Mon, 10 Jun 2002 14:42:55 -0400
From: Christopher Faylor <cgf AT redhat DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: struct hostent
Message-ID: <20020610184255.GB19457@redhat.com>
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References: <Pine DOT GSO DOT 4 DOT 30L DOT 0206101405310 DOT 21513-100000 AT biohazard-cafe DOT mit DOT edu>
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On Mon, Jun 10, 2002 at 02:12:19PM -0400, David E Euresti wrote:
>Hello everytime I reinstall a new snapshot of cygwin, I have to modify one
>header file, netdb.h
>
>netdb.h in cygwin declares
>struct	hostent {
>	const char	*h_name;	/* official name of host */
>	char	**h_aliases;	/* alias list */
>	short	h_addrtype;	/* host address type */
>	short	h_length;	/* length of address */
>	char	**h_addr_list;	/* list of addresses from name server */
>#define	h_addr	h_addr_list[0]	/* address, for backward compatiblity */
>};
>
>Except Solaris declares it as
>struct	hostent {
>	char	*h_name;	/* official name of host */
>	char	**h_aliases;	/* alias list */
>	short	h_addrtype;	/* host address type */
>	short	h_length;	/* length of address */
>	char	**h_addr_list;	/* list of addresses from name server */
>#define	h_addr	h_addr_list[0]	/* address, for backward compatiblity */
>};
>
>And even MSDN declares it as
>struct hostent {
>    char FAR *       h_name;
>    char FAR * FAR * h_aliases;
>    short            h_addrtype;
>    short            h_length;
>    char FAR * FAR * h_addr_list;
>};
>
>notice how h_name is not const.
>Is there any reason why h_name is const in cygwin?

Apparently it's to accommodate an ancient hack in gethostbyname for
dealing with numeric IP addresses.

Looking at gethostbyname, I can see some dreaded static variables;
meaning that this function is not really thread-safe.  It should be
possible to rewrite this to do the right thing, however.  Do you have
an assignment with Red Hat?  We'll gladly accept a patch, if so.

cgf

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