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       ares_library_init - c-ares library initialization


       #include <ares.h>

       int ares_library_init(int flags)

       cc file.c -lcares


       The  ares_library_init  function  performs  initializations  internally
       required by the c-ares library that must take place  before  any  other
       function provided by c-ares can be used in a program.

       This  function  must  be  called one time within the life of a program,
       before the program actually executes any other c-ares library function.
       Initializations  done by this function remain effective until a call to
       ares_library_cleanup(3) is performed.

       Successive calls to this function do nothing, only the first call  done
       when c-ares is in an uninitialized state is actually effective.

       The  flags  parameter  is a bit pattern that tells c-ares exactly which
       features should be initialized, as described  below.  Set  the  desired
       bits  by  ORing  the  values  together.  In normal operation you should
       specify ARES_LIB_INIT_ALL. Don’t use any other  value  unless  you  are
       familiar with it and trying to control some internal c-ares feature.

       This function is not thread safe.  You have to call it once the program
       has started, but this call must be done before the program  starts  any
       other  thread.  This  is required to avoid potential race conditions in
       library   initialization,   and   also   due   to   the    fact    that
       ares_library_init(3) might call functions from other libraries that are
       thread unsafe, and could conflict with any other thread that is already
       using these other libraries.

       Win32/64  application DLLs shall not call ares_library_init(3) from the
       DllMain function. Doing so will produce deadlocks and other problems.


            Initialize everything possible. This sets all known bits.

            Initialize Win32/64 specific libraries.

            Initialize nothing extra. This sets no bit.


       Upon  successful  completion,  ares_library_init()   will   return   0.
       Otherwise,  a  non-zero  error  number will be returned to indicate the
       error. Except for ares_strerror(3), you shall not call any other c-ares
       function upon ares_library_init(3) failure.


       This  function  was first introduced in c-ares version 1.7.0 along with
       the definition of preprocessor symbol  CARES_HAVE_ARES_LIBRARY_INIT  as
       an indication of the availability of this function.

       Since  the  introduction of this function it is absolutely mandatory to
       call it for any Win32/64 program using c-ares.

       Non-Win32/64 systems can still use c-ares version 1.7.0 without calling
       ares_library_init(3)  due to the fact that currently it is nearly a do-
       nothing function on non-Win32/64 platforms at this point.


       ares_library_cleanup(3), ares_strerror(3)


       Yang Tse

       Copyright 1998 by the Massachusetts Institute of Technology.
       Copyright (C) 2004-2009 by Daniel Stenberg.

                                  19 May 2009