stdlib: Describe __cxa_finalize usage in function comment

Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
This commit is contained in:
Florian Weimer 2024-06-03 19:04:58 +02:00
parent afe42e935b
commit 992daa0b4b

View File

@ -24,7 +24,22 @@
/* If D is non-NULL, call all functions registered with `__cxa_atexit'
with the same dso handle. Otherwise, if D is NULL, call all of the
registered handlers. */
registered handlers.
A __cxa_finalize function is declared in the libstdc++ <cxxabi.h>
header, and the libstdc++ implementation calls this function. GCC
calls the glibc variant directly from its CRT files, from an ELF
destructor. this call always passes a non-null D argument. In the
current implementation, the GCC-provided __cxa_finalize call is
responsible for removing the registered __cxa_atexit (C++)
destructors of an object that is undergoing dlclose. Note that
this is specific to dlclose. During process termination, glibc
invokes the __run_exit_handlers, which calls registered
__cxa_atexit (C++) destructors in reverse registration order,
across all objects. The subsequent GCC-provided __cxa_finalize
calls (which are ordered according to ELF object dependencies, not
__cxa_atexit call order, and group destructor calls per object
during dlclose) do not result in further destructor invocations. */
void
__cxa_finalize (void *d)
{