ares_library_init(3) [debian man page]

ARES_LIBRARY_INIT(3)					     Library Functions Manual					      ARES_LIBRARY_INIT(3)

NAME

       ares_library_init - c-ares library initialization

SYNOPSIS

       #include <ares.h>

       int ares_library_init(int flags)

       cc file.c -lcares

DESCRIPTION

       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  prob-
       lems.

FLAGS

       ARES_LIB_INIT_ALL
	    Initialize everything possible. This sets all known bits.

       ARES_LIB_INIT_WIN32
	    Initialize Win32/64 specific libraries.

       ARES_LIB_INIT_NONE
	    Initialize nothing extra. This sets no bit.

RETURN VALUE

       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.

AVAILABILITY

       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.

SEE ALSO

       ares_library_cleanup(3), ares_strerror(3)

AUTHOR

       Yang Tse

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

								    19 May 2009 					      ARES_LIBRARY_INIT(3)

Check Out this Related Man Page

ARES_GET_SERVERS(3)					     Library Functions Manual					       ARES_GET_SERVERS(3)

NAME

       ares_get_servers - Retrieve name servers from an initialized ares_channel

SYNOPSIS

       #include <ares.h>

       int ares_get_servers(ares_channel channel, struct ares_addr_node **servers)

DESCRIPTION

       The  ares_get_servers(3)  function  retrieves  name  servers configuration from the channel data identified by channel, as a linked list of
       ares_addr_node structs storing a pointer to the first node at the address specified by servers.

       Function caller may traverse the returned name server linked list, or may use it directly as suitable  input  for  the  ares_set_servers(3)
       function, but shall not shrink or extend the list on its own.

       Each node of the name server linked list is stored in memory dynamically allocated and managed by c-ares. It is the caller's responsibility
       to free the resulting linked list, using ares_free_data(3) , once the caller does not need it any longer.

       This function is capable of handling IPv4 and IPv6 name	server	addresses  simultaneously,  rendering  ares_save_options(3)  with  optmask
       ARES_OPT_SERVERS functionally obsolete except for IPv4-only name server usage.

RETURN VALUES

       ares_get_servers(3) may return any of the following values:

       ARES_SUCCESS   The name servers configuration was successfuly retrieved

       ARES_ENOMEM    The memory was exhausted

       ARES_ENODATA   The channel data identified by channel was invalid.

SEE ALSO

       ares_set_servers(3), ares_init_options(3), ares_save_options(3)

AVAILABILITY

       ares_get_servers(3) was added in c-ares 1.7.1

AUTHOR

       Implementation of this function and associated library internals are based on code, comments and feedback provided in November and December
       of 2008 by Daniel Stenberg, Gregor Jasny, Phil Blundell and Yang Tse, December 2009 by Cedric Bail, February 2010 by Jakub Hrozek. On March
       2010 Yang Tse shuffled all the bits and this function popped out.
       Copyright 1998 by the Massachusetts Institute of Technology.
       Copyright (C) 2008-2010 by Daniel Stenberg

								   5 March 2010 					       ARES_GET_SERVERS(3)

Linux and UNIX Man Pages

ares_library_init(3) [debian man page]

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