Code:
NAME
resolver -- resolver configuration file
SYNOPSIS
resolv.conf
DESCRIPTION
The resolver(3) is a set of routines in the C library which provide
access to the Internet Domain Name System. The resolver configuration
file contains information that is read by the resolver routines the first
time they are invoked by a process. The file is designed to be human
readable and contains a list of keywords with values that provide various
types of resolver information.
If you are correct the cause would be the
libc library.