ares_library_cleanup - ares library deinitialization
#include <ares.h> void ares_library_cleanup(void)
ARES_LIBRARY_CLEANUP(3) Library Functions Manual ARES_LIBRARY_CLEANUP(3) NAME ares_library_cleanup - c-ares library deinitialization SYNOPSIS #include <ares.h> void ares_library_cleanup(void) DESCRIPTION The ares_library_cleanup function uninitializes the c-ares library, freeing all resources previously acquired by ares_library_init(3) when the library was initialized, provided there was only one single previ- ous call to ares_library_init(3). If there was more than one previous call to ares_library_init(3), this function uninitializes the c-ares library only if it is the call matching the call to ares_library_init(3) which initialized the library (usually the very first call to ares_library_init(3)). Other calls to ares_library_cleanup(3) have no effect other than decrementing an internal counter. This function must be called when the program using c-ares will no longer need any c-ares function. Once the program has called ares_library_cleanup(3) sufficiently often such that the library is uninitialised, it shall not make any further call to any c-ares func- tion. This function does not cancel any pending c-ares lookups or requests previously done. Program must use ares_cancel(3) for this purpose. This function is not thread safe. You have to call it once the program is about to terminate, but this call must be done once the program has terminated every single thread that it could have initiated. This is required to avoid potential race conditions in library deinitializa- tion, and also due to the fact that ares_library_cleanup(3) might call functions from other libraries that are thread unsafe, and could con- flict with any other thread that is already using these other libraries. Win32/64 application DLLs shall not call ares_library_cleanup(3) from the DllMain function. Doing so will produce deadlocks and other prob- lems. AVAILABILITY This function was first introduced in c-ares version 1.7.0 along with the definition of preprocessor symbol CARES_HAVE_ARES_LIBRARY_CLEANUP as an indication of the availability of this function. Reference count- ing in ares_library_init() and ares_library_cleanup(), which requires calls to the former function to match calls to the latter, is present since c-ares version 1.10.0. Earlier versions would deinitialize the library on the first call to ares_library_cleanup(). 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_cleanup(3) due to the fact that currently it is nearly a do-nothing function on non-Win32/64 platforms. ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+------------------+ |Availability | library/libcares | +---------------+------------------+ |Stability | Volatile | +---------------+------------------+ SEE ALSO ares_library_init(3), ares_cancel(3) AUTHOR Yang Tse Copyright 1998 by the Massachusetts Institute of Technology. Copyright (C) 2004-2009 by Daniel Stenberg. NOTES Source code for open source software components in Oracle Solaris can be found at https://www.oracle.com/downloads/opensource/solaris-source- code-downloads.html. This software was built from source available at https://github.com/oracle/solaris-userland. The original community source was downloaded from https://c-ares.haxx.se/download/c- ares-1.17.2.tar.gz. Further information about this software can be found on the open source community website at https://c-ares.haxx.se/. 19 May 2009 ARES_LIBRARY_CLEANUP(3)