threads within an embedded python interpreter

[anonymous]

BPO	221327
Nosy	@gvanrossum, @loewis, @akuchling
Files	init.diff

^{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 = 'https://github.com/loewis'
closed_at = <Date 2003-03-02.13:27:07.000>
created_at = <Date 2000-11-03.20:31:21.000>
labels = ['docs']
title = 'threads within an embedded python interpreter'
updated_at = <Date 2003-03-02.13:27:07.000>
user = 'https://bugs.python.org/anonymous'

bugs.python.org fields:

activity = <Date 2003-03-02.13:27:07.000>
actor = 'gvanrossum'
assignee = 'loewis'
closed = True
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2000-11-03.20:31:21.000>
creator = 'anonymous'
dependencies = []
files = ['7']
hgrepos = []
issue_num = 221327
keywords = []
message_count = 8.0
messages = ['2325', '2326', '2327', '2328', '2329', '2330', '2331', '2332']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'nobody', 'loewis', 'jhylton', 'akuchling']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue221327'
versions = []

[nobody]

I have an application which I am required to embedd a python interpreter inside of a C++ application. The python script creates a separate thread of control to handle a TCP/IP socket connection. The thread can send data just find but hangs on the socket 'recv' fnction.

After a dya of debugging my code I went into the python socketmodule.c and at line 1082 I commented out the thread protection code:

/Py_BEGIN_ALLOW_THREADS/
n = recv(s->sock_fd, PyString_AsString(buf), len, flags);
/Py_END_ALLOW_THREADS/

I then recompiled the python library and then recompiled my C++ app and everything worked just fine.

The problem does not exist when I run the script alone using the python interpreter. Only when I embedd the interpreter, so this is some sort of configuration issue.

David Schere
Email: david_schere@yahoo.com

[gvanrossum]

Most likely, the problem is not the socket module but how you call Python code from a thread that was started from C/C++. Look at t_bootstrap() in threadmodule.c for an example on what to do. (And yes, it's tricky.) There should also be something in the Python/C API documentation about this.

I'm not closing the bug report since this is really a documentation issue; it needs to be documented better. I'll assign it to Fred.

[nobody]

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Now u pay,.

[jhylton]

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user_id=31392

Probably ought to fix this for 2.3

[gvanrossum]

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user_id=6380

but is it a doco bug or not?

[loewis]

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user_id=21627

Doc/api/init.tex already has a paragraph about calling
Python from a C thread; this patch adds a cookbook example.

[akuchling]

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user_id=11375

Typo in init.diff: "interpeter" -> "interpReter" in first line.

Any reason not to check in the example and close the bug?

[gvanrossum]

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Checked in.