There is a constant definition error in errno.py

[lktoken]

BPO	34143
Nosy	@ronaldoussoren, @ned-deily, @tirkarthi, @lktoken
Files	pythonbug.png: Screenshot of the error section

^{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 2018-07-19.19:26:29.869>
created_at = <Date 2018-07-18.07:26:34.228>
labels = ['OS-mac', 'invalid', 'type-bug', 'library']
title = 'There is a constant definition error in errno.py'
updated_at = <Date 2018-07-19.19:26:29.868>
user = 'https://github.com/lktoken'

bugs.python.org fields:

activity = <Date 2018-07-19.19:26:29.868>
actor = 'brett.cannon'
assignee = 'none'
closed = True
closed_date = <Date 2018-07-19.19:26:29.869>
closer = 'brett.cannon'
components = ['Library (Lib)', 'macOS']
creation = <Date 2018-07-18.07:26:34.228>
creator = 'lktoken'
dependencies = []
files = ['47703']
hgrepos = []
issue_num = 34143
keywords = []
message_count = 8.0
messages = ['321863', '321871', '321872', '321932', '321933', '321935', '321936', '321962']
nosy_count = 4.0
nosy_names = ['ronaldoussoren', 'ned.deily', 'xtreak', 'lktoken']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue34143'
versions = ['Python 2.7']

[lktoken]

In errno.py, the constant EDEADLK has a defined value of 11, and the constant EAGAIN has a defined value of 35, which is exactly the opposite of the linux constant definition. See: https://www.thegeekstuff.com/2010/10/linux -error-codes/.

[tirkarthi]

Can you please add some info on how the errorcode dictionary is generated as shown in the picture along with your OS, system information? They seem to have the right values as per the Linux error codes in my Ubuntu box. I might be wrong on the OS on which this happens since you have mentioned it's the opposite of Linux.

cpython git:(master) ✗ rlwrap ./python
Python 3.8.0a0 (heads/master:35c0809, Jul 16 2018, 10:29:23)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import errno
>>> errno.EDEADLK
35
>>> errno.EAGAIN
11

➜  cpython git:(master) ✗ rlwrap python2.7
Python 2.7.12 (default, Dec  4 2017, 14:50:18)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import errno
>>> errno.EDEADLK
35
>>> errno.EAGAIN
11

Machine details and values in header files as below

➜ cpython git:(master) ✗ rg 'EDEADLK|EAGAIN' /usr/include/asm-generic/errno-base.h /usr/include/asm-generic/errno.h

/usr/include/asm-generic/errno-base.h
14:#define EAGAIN 11 /* Try again */

/usr/include/asm-generic/errno.h
6:#define EDEADLK 35 /* Resource deadlock would occur */

➜ cpython git:(master) ✗ uname -a
Linux ubuntu-s-1vcpu-1gb-blr1-01 4.4.0-127-generic #153-Ubuntu SMP Sat May 19 10:58:46 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Thanks

[tirkarthi]

Please ignore about how it's generated. I tried errno.errorcode and can get the dictionary as in the picture with https://docs.python.org/3.8/library/errno.html#errno.errorcode. I think this has to be used as below and also would like to know how other error names have the correct numeric value except for the EDEADLK and EAGAIN which is generated at Modules/errnomodule.c . Using them with os.strerror also gets me the correct information

➜  cpython git:(master) ✗ rlwrap ./python
Python 3.8.0a0 (heads/master:35c0809, Jul 16 2018, 10:29:23)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.strerror(35)
'Resource deadlock avoided'
>>> os.strerror(11)
'Resource temporarily unavailable'

Thanks

[lktoken]

The picture is a screenshot from the IDEA editor on my OSX system. This may be just a problem with the python I am using. So sad.
Python 2.7.10 (default, Oct  6 2017, 22:29:07)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import errno
>>> errno.EDEADLK
11
>>> errno.EAGAIN
35
>>> import os
>>> os.strerror(11)
'Resource deadlock avoided'
>>> os.strerror(35)
'Resource temporarily unavailable'
>>>

Any more, follow your shell commands, I found this:

➜  ~ grep -E 'EDEADLK|EAGAIN' /usr/include/sys/errno.h
#define	EDEADLK		11		/* Resource deadlock avoided */
					/* 11 was EAGAIN */
#define	EAGAIN		35		/* Resource temporarily unavailable */
#define	EWOULDBLOCK	EAGAIN		/* Operation would block */
 
And my OS info:
➜  ~ uname -a
Darwin lktokendeMacBook-Air.local 17.6.0 Darwin Kernel Version 17.6.0: Tue May  8 15:22:16 PDT 2018; root:xnu-4570.61.1~1/RELEASE_X86_64 x86_64

Thank you very much.

[ronaldoussoren]

I’m not sure if I understand correctly. Is your report about the difference in the values of EAGAIN between Linux and macOS?

If so, that is not a bug: the relevant standards only document the name and type of these constants and not their values. The value can and does vary across operating systems.

--
On the road, hence brief.

Op 19 jul. 2018 om 08:16 heeft lktoken <report@bugs.python.org> het volgende geschreven:

lktoken <zhwbchina@gmail.com> added the comment:

The picture is a screenshot from the IDEA editor on my OSX system. This may be just a problem with the python I am using. So sad.
Python 2.7.10 (default, Oct 6 2017, 22:29:07)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import errno
>>> errno.EDEADLK
11
>>> errno.EAGAIN
35
>>> import os
>>> os.strerror(11)
'Resource deadlock avoided'
>>> os.strerror(35)
'Resource temporarily unavailable'
>>>

Any more, follow your shell commands, I found this:

➜ ~ grep -E 'EDEADLK|EAGAIN' /usr/include/sys/errno.h
#define EDEADLK 11 /* Resource deadlock avoided */
/* 11 was EAGAIN */
#define EAGAIN 35 /* Resource temporarily unavailable */
#define EWOULDBLOCK EAGAIN /* Operation would block */

And my OS info:
➜ ~ uname -a
Darwin lktokendeMacBook-Air.local 17.6.0 Darwin Kernel Version 17.6.0: Tue May 8 15:22:16 PDT 2018; root:xnu-4570.61.1~1/RELEASE_X86_64 x86_64

Thank you very much.

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Python tracker <report@bugs.python.org>
<https://bugs.python.org/issue34143\>

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[lktoken]

yes, I agree that this is not a bug.
I used to think that this value is the same in macOS and Linux. Now it seems that I am wrong. And sorry for disturbing you.

[tirkarthi]

Thanks for the details @lktoken. I assumed that you were on Linux and had the opposite values. Verified it on my Mac and they report the same values as yours. I think the values are also different for Windows machines as @ronaldoussoren noted in his comment

EAGAIN - 11
EDEADLK - 36 (Not 35 like Linux)

Ref : https://docs.microsoft.com/en-us/cpp/c-runtime-library/errno-doserrno-sys-errlist-and-sys-nerr

Thanks

[ronaldoussoren]

This is not a bug and the issue can be closed. I’ll do so when I get back to my computer in a couple of days.

--
On the road, hence brief.

Op 19 jul. 2018 om 08:52 heeft Karthikeyan Singaravelan <report@bugs.python.org> het volgende geschreven:

Karthikeyan Singaravelan <tir.karthi@gmail.com> added the comment:

Thanks for the details @lktoken. I assumed that you were on Linux and had the opposite values. Verified it on my Mac and they report the same values as yours. I think the values are also different for Windows machines as @ronaldoussoren noted in his comment

EAGAIN - 11
EDEADLK - 36 (Not 35 like Linux)

Ref : https://docs.microsoft.com/en-us/cpp/c-runtime-library/errno-doserrno-sys-errlist-and-sys-nerr

Thanks

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---

Python tracker <report@bugs.python.org>
<https://bugs.python.org/issue34143\>

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