pthread_atfork is not actually implemented, making some programs fail. Code can probably be borrowed from nptl/sysdeps/unix/sysv/linux/register-atfork.c.

IRC, OFTC, #debian-hurd, 2013-08-21

<pinotree> SRCDIR/opal/mca/memory/linux/arena.c:387: warning: warning:
  pthread_atfork is not implemented and will always fail

Samuel's implementation

TODO.

IRC, OFTC, #debian-hurd, 2013-10-08

<pinotree> youpi: if you need/want to test your pthread_atfork
  implementation, you can check libposix-atfork-perl and its test suite
  (whose test 004 hangs now, with eglibc -93)
<youpi> while it failed previously indeed
<youpi> we might simply need to rebuild perl against it
<youpi> (I see ifdef pthread_atfork in perl)

undefined reference to `starthurd_atfork_prepare_hook'

IRC, freenode, #hurd, 2013-10-16

<teythoon> tschwinge: I'd love to try your cross-gnu tool, the wiki page
  suggests that the list of required source packages is outdated. can you
  give me some hints?
<teythoon> tschwinge: I got this error running cross-gnu:
  http://paste.debian.net/58303/
    make[4]: Leaving directory `/home/teythoon/repos/hurd/cross/src/glibc/setjmp'
    make subdir=string -C ../string ..=../ objdir=/home/teythoon/repos/hurd/cross/obj/glibc -f Makefile -f ../elf/rtld-Rules rtld-all rtld-modules='rtld-strchr.os rtld-strcmp.os rtld-strcpy.os rtld-strlen.os rtld-strnlen.os rtld-memchr.os rtld-memcmp.os rtld-memmove.os rtld-memset.os rtld-mempcpy.os rtld-stpcpy.os rtld-memcpy.os rtld-rawmemchr.os rtld-argz-count.os rtld-argz-extract.os rtld-stpncpy.os'
    make[4]: Entering directory `/home/teythoon/repos/hurd/cross/src/glibc/string'
    make[4]: Leaving directory `/home/teythoon/repos/hurd/cross/src/glibc/string'
    make[4]: Entering directory `/home/teythoon/repos/hurd/cross/src/glibc/string'
    make[4]: Nothing to be done for `rtld-all'.
    make[4]: Leaving directory `/home/teythoon/repos/hurd/cross/src/glibc/string'
    make[3]: Leaving directory `/home/teythoon/repos/hurd/cross/src/glibc/elf'
    i686-pc-gnu-gcc   -shared -static-libgcc -Wl,-O1  -Wl,-z,defs -Wl,-dynamic-linker=/lib/ld.so.1  -B/home/teythoon/repos/hurd/cross/obj/glibc/csu/  -Wl,--version-script=/home/teythoon/repos/hurd/cross/obj/glibc/libc.map -Wl,-soname=libc.so.0.3 -Wl,-z,combreloc -Wl,-z,relro -Wl,--hash-style=both -nostdlib -nostartfiles -e __libc_main -L/home/teythoon/repos/hurd/cross/obj/glibc -L/home/teythoon/repos/hurd/cross/obj/glibc/math -L/home/teythoon/repos/hurd/cross/obj/glibc/elf -L/home/teythoon/repos/hurd/cross/obj/glibc/dlfcn -L/home/teythoon/repos/hurd/cross/obj/glibc/nss -L/home/teythoon/repos/hurd/cross/obj/glibc/nis -L/home/teythoon/repos/hurd/cross/obj/glibc/rt -L/home/teythoon/repos/hurd/cross/obj/glibc/resolv -L/home/teythoon/repos/hurd/cross/obj/glibc/crypt -L/home/teythoon/repos/hurd/cross/obj/glibc/mach -L/home/teythoon/repos/hurd/cross/obj/glibc/hurd -Wl,-rpath-link=/home/teythoon/repos/hurd/cross/obj/glibc:/home/teythoon/repos/hurd/cross/obj/glibc/math:/home/teythoon/repos/hurd/cross/obj/glibc/elf:/home/teythoon/repos/hurd/cross/obj/glibc/dlfcn:/home/teythoon/repos/hurd/cross/obj/glibc/nss:/home/teythoon/repos/hurd/cross/obj/glibc/nis:/home/teythoon/repos/hurd/cross/obj/glibc/rt:/home/teythoon/repos/hurd/cross/obj/glibc/resolv:/home/teythoon/repos/hurd/cross/obj/glibc/crypt:/home/teythoon/repos/hurd/cross/obj/glibc/mach:/home/teythoon/repos/hurd/cross/obj/glibc/hurd -o /home/teythoon/repos/hurd/cross/obj/glibc/libc.so -T /home/teythoon/repos/hurd/cross/obj/glibc/shlib.lds /home/teythoon/repos/hurd/cross/obj/glibc/csu/abi-note.o /home/teythoon/repos/hurd/cross/obj/glibc/elf/soinit.os /home/teythoon/repos/hurd/cross/obj/glibc/libc_pic.os /home/teythoon/repos/hurd/cross/obj/glibc/elf/sofini.os /home/teythoon/repos/hurd/cross/obj/glibc/elf/interp.os /home/teythoon/repos/hurd/cross/obj/glibc/elf/ld.so /home/teythoon/repos/hurd/cross/obj/glibc/mach/libmachuser-link.so /home/teythoon/repos/hurd/cross/obj/glibc/hurd/libhurduser-link.so -lgcc
    /home/teythoon/repos/hurd/cross/obj/glibc/libc_pic.os: In function `__fork':
    /home/teythoon/repos/hurd/cross/src/glibc/posix/../sysdeps/mach/hurd/fork.c:70: undefined reference to `__start__hurd_atfork_prepare_hook'
    /home/teythoon/repos/hurd/cross/lib/gcc/i686-pc-gnu/4.8.1/../../../../i686-pc-gnu/bin/ld: /home/teythoon/repos/hurd/cross/obj/glibc/libc_pic.os: relocation R_386_GOTOFF against undefined hidden symbol `__start__hurd_atfork_prepare_hook' can not be used when making a shared object
    /home/teythoon/repos/hurd/cross/lib/gcc/i686-pc-gnu/4.8.1/../../../../i686-pc-gnu/bin/ld: final link failed: Bad value
    collect2: error: ld returned 1 exit status
    make[2]: *** [/home/teythoon/repos/hurd/cross/obj/glibc/libc.so] Error 1
    make[2]: Leaving directory `/home/teythoon/repos/hurd/cross/src/glibc/elf'
    make[1]: *** [elf/subdir_lib] Error 2
    make[1]: Leaving directory `/home/teythoon/repos/hurd/cross/src/glibc'
    make: *** [all] Error 2
    + rm -f /home/teythoon/repos/hurd/cross/sys_root/lib/ld.so
    + exit 100

    binutils-2.23.2,
    gcc-4.8.1,
    everything else is from git as specified in the wiki.

IRC, freenode, #hurd, 2013-10-24

<AliciaC> in recent glibc commits (tschwinge/Roger_Whittaker branch) there
  are references to _hurd_atfork_* symbols in sysdeps/mach/hurd/fork.c, and
  some _hurd_fork_* symbols, some of the _hurd_fork_* symbols seem to be
  defined in Hurd's boot/frankemul.ld (mostly guessing by their names being
  mentioned, I don't know linker script syntax), but those _hurd_atfork_*
  symbols don't seem to be defined there, are they supposed to be defined
  elsewhere or is th
<AliciaC> does anyone know where the _hurd_atfork_* group of symbols
  referenced in glibc are defined (if anywhere)?
<youpi> AliciaC: it's the DEFINE_HOOK (_hurd_atfork_prepare_hook, (void));
  in glibc/sysdeps/mach/hurd/fork.c
<AliciaC> hm, is that not just a declaration?
<youpi> no, it's a definition, as its name suggests :
<AliciaC> (despite the macro name)
<youpi> :)
<AliciaC> ok
<AliciaC> I should look into it more, I could have sworn I was getting
  undefined references, but maybe the symbol names used are different from
  those defined, but that'd be odd as well, in the same file and all
<AliciaC> I mean, I do get undefined references, but question is if it's to
  things that should have been defined or not
<youpi> what undefined references do you gaT?
<youpi> s/gaT/get
<AliciaC> I'll get back to you once I have that system up again
<AliciaC> youpi: sysdeps/mach/hurd/fork.c:70: undefined reference to
  `__start__hurd_atfork_prepare_hook'
<AliciaC> fork.c:70: 'RUN_HOOK (_hurd_atfork_prepare_hook, ());'
<AliciaC> DEFINE_HOOK (_hurd_atfork_prepare_hook, (void)); is higher up in
  the file
<AliciaC> though there is also this message: build/libc_pic.os: relocation
  R_386_GOTOFF against undefined hidden symbol
  `__start__hurd_atfork_prepare_hook' can not be used when making a shared
  object

id:"[email protected]"