Subprocess puzzle and two questions

Nobody nobody at nowhere.com
Sat Nov 17 01:17:26 CET 2012


On Thu, 15 Nov 2012 20:07:38 -0500, Roy Smith wrote:

>>> gethostbyname() and getaddrinfo() use the NSS (name-service switch)
>> mechanism, which is configured via /etc/nsswitch.conf. Depending upon
>> configuration, hostnames can be looked up via a plain text file
>> (/etc/hosts), Berkeley DB files, DNS, NIS, NIS+, LDAP, WINS, etc.
> 
> Gethostbyname() long predates NSS.

Before NSS there was host.conf, which provided similar functionality
except that the set of mechanisms was fixed (they were built into libc
rather than being dynamically-loaded libraries) and it only applied to
hostnames (NSS is also used for getpwent(), getprotoent(), etc).

> For that matter, I think it even predates DNS (i.e. back to the days
> when /etc/hosts was the *only* way to look up a hostname).
> 
> But, that's a nit.

Indeed; the main point is that gethostbyname() has never been specific to
DNS.



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