Fwd: gnulib posix_spawn_file_actions_addclose

[Bruno Haible]

Forward from Uwe, a long-term NetBSD and GNU libffcall contributor.

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Subject: gnulib posix_spawn_file_actions_addclose
Date: Mittwoch, 7. September 2022, 16:29:32 CEST
From: Valery Ushakov <uwe@stderr.spb.ru>
To: Bruno Haible <bruno@clisp.org>

Hi, Bruno.  It looks like you are the author of the posix_spawn
implementation in gnulib so I wanted to ask a question privately
before spamming bug-gnulib.

On a systems with musl-1.2.3 for its libc the gnulib configure (as
part of m4 1.4.19) detects:

$ grep spawn .log.configure 
checking for spawn.h... yes
checking for posix_spawn_file_actions_addchdir_np... yes
checking for posix_spawn_file_actions_addchdir... no
checking for library containing posix_spawn... none required
checking for posix_spawn... yes
checking whether posix_spawn is declared... yes
checking whether posix_spawn works... yes
checking whether posix_spawn rejects scripts without shebang... yes
checking whether posix_spawnp rejects scripts without shebang... yes
checking whether posix_spawnattr_setschedpolicy is supported... yes
checking whether posix_spawnattr_setschedparam is supported... yes
checking for posix_spawnattr_t... yes
checking for posix_spawn_file_actions_t... yes
checking whether posix_spawn_file_actions_addclose works... yes
checking whether posix_spawn_file_actions_adddup2 works... no
checking whether posix_spawn_file_actions_addopen works... no


The addclose configure test succeeds b/c of this commit:

  
https://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=commitdiff;h=36a838b081de0d2c62970df5b4b8d736d3aebe1d

that makes configure test a negative fd instead of a large fd.
However tests/test-posix_spawn_file_actions_addclose.c still tests for
a large fd too and fails that test.

I wonder if either test-posix_spawn_file_actions_addclose.c should not
check for the "big" fd (and neither should spawn_faction_addclose.c
too?)  or the configure check should be reverted to check for the
"big" fd to make the two match.


Thanks.

-uwe

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