Compilation --without-threads fails

[pitrou]

BPO	5035
Nosy	@amauryfa, @pitrou, @vstinner
Files	object_dump_nothread.patch gil_nothread.patch _sqlite_nothread-2.patch _tkinter_nothread.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2010-03-22.12:08:22.098>
created_at = <Date 2009-01-22.21:24:21.863>
labels = ['build']
title = 'Compilation --without-threads fails'
updated_at = <Date 2010-03-22.12:08:22.096>
user = 'https://github.com/pitrou'

bugs.python.org fields:

activity = <Date 2010-03-22.12:08:22.096>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2010-03-22.12:08:22.098>
closer = 'vstinner'
components = []
creation = <Date 2009-01-22.21:24:21.863>
creator = 'pitrou'
dependencies = []
files = ['12837', '12838', '13431', '13432']
hgrepos = []
issue_num = 5035
keywords = ['patch']
message_count = 17.0
messages = ['80379', '80380', '80400', '80401', '80402', '80403', '80404', '80405', '80406', '80407', '80413', '84242', '84244', '84245', '84282', '84292', '101496']
nosy_count = 5.0
nosy_names = ['amaury.forgeotdarc', 'pitrou', 'vstinner', 'gpolo', 'jnoller']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'compile error'
url = 'https://bugs.python.org/issue5035'
versions = ['Python 2.7']

[pitrou]

libpython2.7.a(object.o): In function _PyObject_Dump': /home/antoine/cpython/__svn__/Objects/object.c:341: undefined reference to PyGILState_Ensure'
/home/antoine/cpython/svn/Objects/object.c:343: undefined reference
to `PyGILState_Release'

[pitrou]

The problem seems to have appeared with:

[svn r67802] bpo-3632: the "pyo" macro from gdbinit can now run when the
GIL is released.

Patch by haypo.

diff -r 68d511e1c4bc -r 584e97b40be9 Objects/object.c
--- a/Objects/object.c  Mon Dec 15 22:47:57 2008 +0100
+++ b/Objects/object.c  Mon Dec 15 23:29:14 2008 +0100
@@ -331,8 +331,11 @@
        if (op == NULL)
                fprintf(stderr, "NULL\n");
        else {
+               PyGILState_STATE gil;
                fprintf(stderr, "object  : ");
+               gil = PyGILState_Ensure();
                (void)PyObject_Print(op, stderr, 0);
+               PyGILState_Release(gil);
                /* XXX(twouters) cast refcount to long until %zd is
                   universally available */
                fprintf(stderr, "\n"

[vstinner]

Oops, here is a fix for my regression.

[vstinner]

Why is PyGILState_Ensure() defined in Include/pystate.h in there is not
thread? PyGILState_Ensure() implementation is conditional (in
Python/pystate.c). Here is a patch to make the definition optional.

[vstinner]

Another patch to fix _sqlite without thread support.

[vstinner]

_multiprocessing modules doesn't compile but I don't know how to fix it:

• conn_poll() has a _save argument, but the argument is not used in
  both conn_poll() implementations (pipe_connection.c and socket_connection.c)
• Modules/_multiprocessing/semaphore.c contains a lot of functions and
  macros for semaphore managment but it looks like thread support is
  required. Eg. compilation fails on a missing symbol: sem_unlink(). The
  function sem_unlink() is defined in system <semaphore.h> and requires
  -lrt or -lpthread compiler flag.

[vstinner]

Here is a patch to remove the unused _save argument of conn_poll()
function from the _multiprocessing mode. It fixes one of the compilation
problem without thread support.

[pitrou]

There is already a separate issue for multiprocessing compilation: bpo-3807

[jnoller]

Victor - there is already another bug and a pending patchbto fix
multiprocessing when thread support is enabled. Please do not focus on
that.

[vstinner]

@pitou and @jnoller: Ok ok, fine, I will check bpo-3807.

[jnoller]

I've committed the fix for bpo-3807 to resolve the mp issues.

[vstinner]

Python trunk is still broken --without-threads. The multiprocessing
issue (bpo-3807) is now closed, so can someone review (or apply?) my
patches?

[vstinner]

Updated and completed patch for _sqlite module (python trunk).

[vstinner]

New patch _tkinter_nothread.patch: fix gcc warnings in _tkinter.

[gpolo]

Victor, I have changed your tkinter patch a bit and applied on r70641.

The issue is marking only python 2.7 right now, aren't these changes
supposed to be applied 26-maint, py3k and 30-maint too ?

[vstinner]

gpolo> Victor, I have changed your tkinter patch a bit and applied on r70641.

Ok, thanks.

gpolo> The issue is marking only python 2.7 right now, aren't these changes
gpolo> supposed to be applied 26-maint, py3k and 30-maint too ?

Since it only fixes warnings, we don't have to "fix" *-maint versions. But I
would like to see your fix in py3k (I think that trunk and py3k should be as
close as possible).

[vstinner]

_tkinter patch (r70641) was backported to py3k as r70707. py3k compiles fine without threads.