In perl.git, the branch smoke-me/davem/win32_exit has been created
<https://perl5.git.perl.org/perl.git/commitdiff/9fafc52ee15897a9f799bf28336e5f7f389a0df7?hp=0000000000000000000000000000000000000000>
at 9fafc52ee15897a9f799bf28336e5f7f389a0df7 (commit)
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commit 9fafc52ee15897a9f799bf28336e5f7f389a0df7
Author: David Mitchell <da...@iabyn.com>
Date: Mon Apr 30 21:42:55 2018 +0100
win323 fork(): honour PERL_EXIT_DESTRUCT_END
RT #132863
The PERL_EXIT_DESTRUCT_END flag in PL_exit_flags is designed to defer
the calling of END blocks in perl_run() to being called from
perl_destruct() instead. On UNIX-like builds, perlmain.c sets this flag.
So main() looks like, in outline:
PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
if (!perl_parse(my_perl, xs_init, argc, argv, (char **)NULL))
perl_run(my_perl);
exitstatus = perl_destruct(my_perl);
which means that it doesn't matter whether perl_parse() finishes
normally or prematurely (e.g. via BEGIN { exit(1) } or BEGIN { die });
in all cases, due to PERL_EXIT_DESTRUCT_END being set, the END blocks
will always be called (from perl_destruct()).
Commit v5.27.7-9-g8e920bd341 added PERL_EXIT_DESTRUCT_END to the
equivalent of main() on other platforms such as win32; this
means that the new tests in t/op/blocks.t pass on win32 too, and all
platforms have the same behaviour for e.g.
END { print "end\n"; } BEGIN { exit 1; } # prints "end"
However, that commit was causing some tests in some CPAN distributions to
hang. These were using the win32 fork() emulation.
PerlProcFork() on win32 clones an interpreter, starts a new thread,
and makes the new thread call win32_start_child(), which
does the rough equivalent of C<perl_run(); perl_destruct();>,
except that it rolls it's own perl_run() equivalent which
*doesn't* honour the PERL_EXIT_DESTRUCT_END flag. So by setting
PERL_EXIT_DESTRUCT_END, END blocks in fork()ed processes were getting
executed twice: once by win32_start_child() emulating perl_run(),
and once by perl_destruct() called from win32_start_child().
This commit makes win32_start_child() honour PERL_EXIT_DESTRUCT_END.
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