Re: lib/53805: dlclose(3) does not interact correctly with atexit(3) callbacks

[Kamil Rytarowski <n54%gmx.com@localhost>]

The following reply was made to PR lib/53805; it has been noted by GNATS.

From: Kamil Rytarowski <n54%gmx.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: lib/53805: dlclose(3) does not interact correctly with atexit(3)
 callbacks
Date: Thu, 20 Dec 2018 19:22:29 +0100

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 From: Kamil Rytarowski <n54%gmx.com@localhost>
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 Subject: Re: lib/53805: dlclose(3) does not interact correctly with atexit(3)
  callbacks
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 There is also specification mentioning this in C++ABI:
 
 https://itanium-cxx-abi.github.io/cxx-abi/abi.html#dso-dtor-motivation
 
 The API specified below is intended to provide standard-conforming
 treatment during normal program exit, which includes executing
 atexit-registered functions in the correct sequence relative to
 constructor-registered destructors, and reasonable treatment during
 early DSO unload (e.g. dlclose).
 
 [...]
 
 I think the most important part is in "Object construction":
 
 "[...] This registration, e.g. __cxa_atexit(f,p,d), is intended to cause
 the call f(p) when DSO d is unloaded [..]" and dlclose(3) causes DSO to
 be unloaded.
 
 and later in "User atexit calls":
 
 "It is expected that implementations supporting both C and C++ will
 integrate this capability into the libc atexit implementation so that
 C-only DSOs will nevertheless interact with C++ programs in a
 C++-standard-conforming manner."
 
 
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