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41d90aaf62
PR-URL: https://github.com/nodejs/node/pull/53155 Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com> Reviewed-By: Michaël Zasso <targos@protonmail.com> Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
67 lines
2.9 KiB
Groff
67 lines
2.9 KiB
Groff
.\"
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.\" Copyright 1998 by the Massachusetts Institute of Technology.
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.\" Copyright (C) 2004-2009 by Daniel Stenberg
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.\" SPDX-License-Identifier: MIT
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.\"
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.TH ARES_LIBRARY_CLEANUP 3 "19 May 2009"
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.SH NAME
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ares_library_cleanup \- c-ares library deinitialization
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.SH SYNOPSIS
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.nf
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#include <ares.h>
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void ares_library_cleanup(void)
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.fi
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.SH DESCRIPTION
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.PP
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The
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.B ares_library_cleanup
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function uninitializes the c-ares library, freeing all resources
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previously acquired by \fIares_library_init(3)\fP when the library
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was initialized, provided there was only one single previous call to
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\fIares_library_init(3)\fP. If there was more than one previous call to
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\fIares_library_init(3)\fP, this function uninitializes the c-ares
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library only if it is the call matching the call to
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\fIares_library_init(3)\fP which initialized the library
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(usually the very first call to \fIares_library_init(3)\fP).
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Other calls to \fIares_library_cleanup(3)\fP have no effect other than
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decrementing an internal counter.
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.PP
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This function must be called when the program using c-ares will
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no longer need any c-ares function. Once the program has called
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\fIares_library_cleanup(3)\fP sufficiently often such that the
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library is uninitialised, it shall not make any further call to any
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c-ares function.
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.PP
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This function does not cancel any pending c-ares lookups or requests
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previously done. Program must use \fIares_cancel(3)\fP for this purpose.
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.PP
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.B This function is not thread safe.
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You have to call it once the program is about to terminate, but this call must
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be done once the program has terminated every single thread that it could have
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initiated. This is required to avoid potential race conditions in library
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deinitialization, and also due to the fact that \fIares_library_cleanup(3)\fP
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might call functions from other libraries that are thread unsafe, and could
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conflict with any other thread that is already using these other libraries.
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.PP
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Win32/64 application DLLs shall not call \fIares_library_cleanup(3)\fP from
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the DllMain function. Doing so will produce deadlocks and other problems.
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.SH AVAILABILITY
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This function was first introduced in c-ares version 1.7.0 along with the
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definition of preprocessor symbol \fICARES_HAVE_ARES_LIBRARY_CLEANUP\fP as an
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indication of the availability of this function. Reference counting in
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\fIares_library_init(3)\fP and \fIares_library_cleanup(3)\fP, which requires
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calls to the former function to match calls to the latter, is present since
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c-ares version 1.10.0. Earlier versions would deinitialize the library on the
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first call to \fIares_library_cleanup(3)\fP.
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.PP
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Since the introduction of this function, it is absolutely mandatory to call it
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for any Win32/64 program using c-ares.
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.PP
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Non-Win32/64 systems can still use c-ares version 1.7.0 without calling
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\fIares_library_cleanup(3)\fP due to the fact that \fIcurrently\fP it is nearly
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a do-nothing function on non-Win32/64 platforms.
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.SH SEE ALSO
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.BR ares_library_init (3),
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.BR ares_cancel (3)
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