import os
s = os.sys.stdin.buffer.read(1024*32)
failed with
D:\Projects\pytools>python t1.py
Traceback (most recent call last):
File "t1.py", line 2, in <module>
s = os.sys.stdin.buffer.read(1024*32)
OSError: [Errno 12] Not enough space
buf if given buflen = 1024*32-1 then it goes right
import os
s = os.sys.stdin.buffer.read(1024*32-1)
if you run python t1.py, then the process blocked and waiting for input as expect.
Why python3.3 have 1024*32-1 buffer length limitation? Is it system different, or just a the same for all systems? How can we remove this limitation?
BTW: i using windows 7 python 32 bit version 3.3
We start by looking at the source of os module here, where line 26 reads
import sys, errno
This tells us that os.sys is just a reference to the standard sys module.
Then we head over to the source of the sys module, where in line 1593 we find the following comment (thankfully someone put it there...):
/* stdin/stdout/stderr are now set by pythonrun.c */
Then we go to the pythonrun.c file, where we meet the following code in line 1086:
std = create_stdio(iomod, fd, 0, "<stdin>", encoding, errors);
and this on line 1091:
PySys_SetObject("stdin", std);
Then we look for definition of create_stdio() function which we find in line 910. We look for the return value of this function which is on line 999 and looks like this:
return stream;
Now we have to find out what the stream is. It's the return value of function _PyObject_CallMethodId() called in line 984.
I hope you see the flow - try to follow from here.
Related
I am following the SWIG tutorial and I'm currently on the section: "32.9.1 Converting Python list to a char **". The example in question returns a malloc error on my machine:
import example
example.print_args(["a","bc","dc"])
python(57911,0x10bd32e00) malloc: *** error for object 0x7f7ee0406b90: pointer being freed was not allocated
python(57911,0x10bd32e00) malloc: *** set a breakpoint in malloc_error_break to debug
1 57911 abort python
1 57911 abort python
The error is unexpected as this is exactly the code that the tutorial offers. Any help welcome! Thanks in advance
Specs:
MacOS Big Sur
Python 3.8
C++17
Here are my setup.py (the whole archive for reproducibility):
#!/usr/bin/env python
"""
setup.py file for SWIG example
"""
from distutils.core import setup, Extension
import os
import sys
import glob
# gather up all the source files
srcFiles = ['example.i']
includeDirs = []
srcDir = os.path.abspath('src')
for root, dirnames, filenames in os.walk(srcDir):
for dirname in dirnames:
absPath = os.path.join(root, dirname)
globStr = "%s/*.c*" % absPath
files = glob.glob(globStr)
includeDirs.append(absPath)
srcFiles += files
extra_args = ['-stdlib=libc++', '-mmacosx-version-min=10.7', '-std=c++17', '-fno-rtti']
os.environ["CC"] = 'clang++'
#
example_module = Extension('_example',
srcFiles, # + ['example.cpp'], # ['example_wrap.cxx', 'example.cpp'],
include_dirs=includeDirs,
swig_opts=['-c++'],
extra_compile_args=extra_args,
)
setup(name='example',
version='0.1',
author="SWIG Docs",
description="""Simple swig example from docs""",
ext_modules=[example_module],
py_modules=["example"],
)
The example code would work with Python 2, but has a bug as well as a syntax change for Python 3. char** must be passed byte strings, which are the default in Python 2 when using "string" syntax, but need a leading b, e.g. b"string" in Python 3.
This works:
import example
example.print_args([b"a",b"bc",b"dc"])
The crash is due to a bug calling free twice if an incorrect parameter type is found. Make the following change to the example:
if (PyString_Check(o)) {
$1[i] = PyString_AsString(PyList_GetItem($input, i));
} else {
//free($1); // REMOVE THIS FREE
PyErr_SetString(PyExc_TypeError, "list must contain strings");
SWIG_fail;
SWIG_fail; ends up called the freearg typemap, which calls free a second time. With this change, you should see the following if passing incorrect arguments, such as a non-list or Unicode strings instead of byte strings:
>>> import argv
>>> argv.print_args(1)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\argv.py", line 66, in print_args
return _argv.print_args(argv)
TypeError: not a list
>>> argv.print_args(['abc','def'])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\argv.py", line 66, in print_args
return _argv.print_args(argv)
TypeError: list must contain strings
>>> argv.print_args([b'abc',b'def'])
argv[0] = abc
argv[1] = def
2
Changing the error message to "list must contain byte strings" would help as well 😊
I have executed Pylepton_capture
https://github.com/groupgets/pylepton
But I got this error message
Environment: Raspberry Pi 4
Traceback (most recent call last):
File "./pylepton_capture", line 37, in <module>
image = capture(flip_v = options.flip_v, device = options.device)
File "./pylepton_capture", line 10, in capture
a,_ = l.capture()
File "/home/pi/pylepton/pylepton/Lepton.py", line 153, in capture
Lepton.capture_segment(self.__handle, self.__xmit_buf, self.__msg_size, self.__capture_buf[0])
File "/home/pi/pylepton/pylepton/Lepton.py", line 125, in capture_segment
ret = ioctl(handle, iow, xs_buf[xs_size * (60 - messages):], True)
IOError: [Errno 90] Message too long
I guess your problems comes from using Lepton 3.x, which takes lager resolution images than Lepton 2.x (160x120 vs 80x60)
If so, first you have to use the git branch for this model, either lepton3 or lepton3-dev (which are in Python2)
If the problem continues, maybe you have to increase the SPI buffer size to manage such big images (as explained here):
Edit /boot/cmdline.txt and add in the end:
spidev.bufsiz=65535
Then reboot your raspberry and check it worked with:
cat /sys/module/spidev/parameters/bufsiz
I hope this works for you
EDIT:
Check the related Github issue. Other solutios like increasing the Lepton.SPIDEV_MESSAGE_LIMIT value may help also
I am trying to use glog in my python code and when I am trying to import, it throws the following error:
/usr/local/lib/python2.7/dist-packages/glog.py:171: RuntimeWarning:
Trying to access flag verbosity before flags were parsed. This will raise
an exception in the future.
setLevel(FLAGS.verbosity)
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/glog.py", line 171, in
<module>
setLevel(FLAGS.verbosity)
File "/usr/local/lib/python2.7/dist-packages/gflags/flagvalues.py", line
390, in __getattr__
traceback.print_stack()
E0602 09:45:07.674463 4695 flagvalues.py:399] Trying to access flag
verbosity before flags were parsed.
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/gflags/flagvalues.py", line
391, in __getattr__
raise exceptions.UnparsedFlagAccessError(error_message)
UnparsedFlagAccessError: Trying to access flag verbosity before
flags were parsed.
My code is as follows.
import gflags
import glog as log
I have searched online but haven't got any information about the python version of glog. I think this error has to do something with gflags and glog together. Can anyone please explain what is going wrong ?
I have the same issue. After checking the code, it seems some kind of bug of glog.
When import glog is intercepted, it assumes gflags.GFLAGS has been initiated, and tries to read gflags.GFLAGS.verbosity, which actually is not guaranteed to be initialized in most cases.
For example, the following code will throw exception:
import gflags
import glog
import sys
if __name__ == "__main__":
gflags.FLAGS(sys.argv)
# do something.
Since when import glog is intercepted, it reads FLAGS.vebosity, but since glfags.FLAGS(sys.argv) is not executed yet, reading from FLAGS will fail.
So we have to make sure import gflags intercepted after GFLAGS being initialized, the only solution I could think of is putting import glog in another file instead of the main py script.
For example, in main script:
import gflags
import sys
# DON'T IMPORT ANYTHING that evolves of 'glog'
FLAGS = gflags.FLAGS
if __name__ == "__main__":
argv = FLAGS(sys.argv)
# import any modle that uses 'glog'
import your_other_module
your_other_module.do_something()
First of all, here's the code
#!/usr/bin/env python3.4
import libtorrent as lt
import os
fs = lt.file_storage()
lt.add_files(fs, "/var/mirror/packages/") # There are two files in this directory
t = lt.create_torrent(fs, flags = 1&8&16) # 1 = Optimization, 8 = Symbolic links, 16 = calculate file hashes.
t.add_tracker("udp://tracker.[private].com:80")
print(os.path.isdir("/var/mirror/packages/"))
lt.set_piece_hashes(t,"/var/mirror/packages/")
print(t.generate())
And here's what happens when I run it
True
Traceback (most recent call last):
File "./test.py", line 9, in <module>
lt.set_piece_hashes(t,"/var/mirror/packages/")
RuntimeError: No such file or directory
This is the page I got this from
I have browsed around the bindings, but I can't find the set_piece_hashes sources. It returns the same error code when I change the path to "." or "/" (keeping the add_files path the same)
Anyone know what I'm doing wrong? I can't find any sort of documentation other than the site I linked above
Turns out set_piece_hashes wants the parent directory of the directory you created the filestore with. After I fixed that, I now get another error, which is a known bug in libtorrent here
I am trying to setup a program where when someone enters a command it will run that command which is a script in a sub folder called "lib".
Here is my code:
import os
while 1:
cmd = input(' >: ')
for file in os.listdir('lib'):
if file.endswith('.py'):
try:
os.system(str(cmd + '.py'))
except FileNotFoundError:
print('Command Not Found.')
I have a file: lib/new_user.py But when I try to run it I get this error:
Traceback (most recent call last):
File "C:/Users/Daniel/Desktop/Wasm/Exec.py", line 8, in <module>
exec(str(cmd + '.py'))
File "<string>", line 1, in <module>
NameError: name 'new_user' is not defined
Does anyone know a way around this? I would prefer if the script would be able to be executed under the same window so it doesn't open a completely new one up to run the code there. This may be a really Noob question but I have not been able to find anything on this.
Thanks,
Daniel Alexander
os.system(os.path.join('lib', cmd + '.py'))
You're invoking new_user.py but it is not in the current directory. You need to construct lib/new_user.py.
(I'm not sure what any of this has to do with windows.)
However, a better approach for executing Python code from Python is making them into modules and using import:
import importlib
cmd_module = importlib.import_module(cmd, 'lib')
cmd_module.execute()
(Assuming you have a function execute defined in lib/new_user.py)