On most Unix systems the resolver timeout is configurable in /etc/resolv.conf. For instance, on Linux, man resolv.conf says: 
options
  Options allows certain internal resolver variables to
  be  modified. The syntax is

           options option ...

  where option is one of the following:

  ...

    timeout:n
      sets  the amount of time the resolver will wait for a
      response from a remote name server before retrying the
      query via a different name server.  Measured in seconds,
      the default is RES_TIMEOUT (currently 5, see <resolv.h>).
The drawback is that it is a system wide setting that (AFAIK) can not be changed for specific applications.

update: hey!, actually it can be changed in a per process manner... 

  The  options keyword of a system's resolv.conf file
  can be amended on a per-process basis by setting the
  environment  variable "RES_OPTIONS" to  a space-separated
  list of resolver options as explained above under
  options.
So, probably doing... 
$ENV{RES_OPTIONS} = "timeout:$timeout";

[download]
before calling gethostbyname will do what you want!

In reply to Re: Timout a gethostbyaddr? by salva
in thread Timout a gethostbyaddr? by rementis

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