As described in: http://bugs.python.org/issue22139, the python27.dll is installed in the windows systems (in my case C:\Windows\Systems32) folder.
But I would like to know why? Why is it not installed next to the python.exe, for example in C:\Python27\?
Reason I ask: I've made a mercurial hook in python that our developers need to use to check if the commit message is valid. It checks a.o. for a valid JIRA issue number. To prevent all our developers to install python themselves and install the required modules manually (a lot of work and errorprone), I zipped the python installation and asked the developers to unzip it locally. But they can't run it, because the python27.dll is missing, or worse, they already have another minor version of python installed, and the hook will fail due to the wrong python27.dll used. Confusing.
If I just add the python27.dll (the correct version) to the zip file, it all seems to work great. So, why is it not installed in that location in the first place? What is the advantage of installing it in C:\Windows\System32?
Hope someone can explain this to me!
Thanks in advance,
Tallandtree.
I use the Anaconda Python distribution from http://continuum.io. They put python27.dll into c:\anaconda right next to its python.exe. This distribution is also superior in that you can have multiple python environments with precisely the packages you need and switch between them easily (http://conda.pydata.org/docs/using/envs.html). You can also get the package list of one of your environments and distribute it to others.
I recommend this Python distribution over the one from python.org and Enthought, because of this issue.
.dlls are quite windows-specific files. I imagine you will have shared object (.so) files for LINUX/UNIX-specific Python stuff? You said your developer's couldn't run it, because they didn't have the correct DLL (i.e. the one relevant to their Python installation).
Also, the advantage of installing it to System32 is that it's in the default PATH. Additionally, if any other application is internally using Python and require access to the .dll file, and also NOT reference your Python directory, they will probably be looking for a location that "Actually" exists (I wanted to say guaranteed to exist, but......never mind). That location would be `C:/windows/Systems32'.
I found it to work just fine to put python27.dll in the Python directory (c:\Python27 or wherever). As long as it's in the PATH, it seems to work. I did this for a "relocatable" installation of Python. I can copy the installation directory to a Windows machine that has no Python installed, set the PATH to include that directory, and run Python, including all the libraries I had installed with pip install on the original machine.
Related
I am trying to install GeoDjango what turns out to be much harder than I thought. After I installed the OSGeo4W on my 64 Bit Windows 10 system I set everything up in the settings.py file but now I get this error:
FileNotFoundError: Could not find module 'C:\OSGeo4W\bin\gdal304.dll' (or one of its dependencies). Try using the full path with constructor syntax.
I also set the GDAL_LIBRARY_PATH but it just won't work.
GDAL_LIBRARY_PATH = "C:\\OSGeo4W\\bin\\gdal304.dll"
This is my C:\OSGeo4W\bin path and as you can see the gdal304.dll file is there
My Python is on version 3.10.6
Django is on version 4.1
I already tried to solve it by myself for a week but slowly I have no idea left on what to do
I ran into this problem too, since I updated my old GEO Django Setup today.
You may use a Docker Image as suggested by the others, but I prefere a native solution, since I don't want to spin up Docker every time I start coding.
Your solution is in the brackets: (or one of its dependencies)
You may look up the transitive dependendencies from gdal304.dll. There are several tools for this (see here). I'm using here now the Git integrated MinGW - Shell that has ldd installed. This should be the case for any (newer) Git installation on Windows.
As you can see, some dependencies are already fullfilled from your operating system. Others that are missing, have to be fullfilled from OSGeo4W. If you compare this with your bin directory from OSGeo4W you will see the Problem:
Sadly a simple "renaming" does not the trick. I was lucky and had not yet deleted my old OSGeo4W version. In the old files I then found the necessary DLL.
So, long story short: You need the jpeg.dll file.
There are sites like "windll.com" or "dll-files.com", but I would not recommend using them. I don't trust these sites. You may install something like "MSYS2", "Cygwin" or even "MVSC", install the "libjpeg-turbo" library and then finally copy & paste the necessary DLL file.
This is also suggested on the official Site for libjpeg-turbo: https://libjpeg-turbo.org/Documentation/OfficialBinaries
But this seems like a lot of work for someone who just want to have the DLL file, but then again: Never download a library blindly from the Internet and load it into your application. These libraries could do anthing!
I am unable to use the Ximea API (python) on linux. The documentation makes it seem like I only have to install the software package (documentation link 1/2) and the library will be available for import in any python script (documentation link 2/2). This is not the case. In windows, one can just copy-past the library from the installation folder. This is not possible in linux : the folder /opt/XIMEA does contain the python example scripts, but it does not contain the library folder itself.
Where can I find the python library folder for linux? How should I go about installing this in conda or another virtual environment?
Regards,
Jan
The answer was provided to me via the XIMEA helpdesk.
Hello,
You are right that the python xiapi is not usable after installation
without further steps to ensure so in some cases. There seems to be a
compatibility issue with the latest version of python and our software
package installation script, because of which the files aren't copied
correctly to the right location. We will work on analyzing and fixing
this, and to do so, we would appreciate if you could provide us with a
few more information. Please send us a xiCOP report, version of Python
you are using, and the output of the software package installation
script if possible. These may help us find out where exactly the
problem is. Thank you for your feedback, it is helping us greatly to
improve our products.
Meanwhile, in the next steps I'll help you copy the files manually to
get the API to work right now:
Locate the downloaded and unzipped folder "XIMEA_Linux_SP" from the first step of our software package installation guide (for me it was
on Desktop but this may differ for you).
Navigate to the /XIMEA_Linux_SP/package/api/Python/ folder and go to either "v2" or "v3" folder according to the python version you're
using. There you'll find a folder "ximea" inside of which are the
xiapi library files.
Locate the folder for python packages on your system (for me it was at /lib/python3/dist-packages/ but it may differ for you).
Copy the whole "ximea" folder from step 2. into your python packages folder (you will probably encounter permission issues, please
use sudo or similar workaround to solve this).
Your python scripts should work now.
I found the right folder by using conda info. This way I could find my conda environments in /home/jan/miniconda3/envs/<ENV NAME>/lib/python3.10/. By simply copy-pasting the ximea folder to this folder, everything worked.
I have Anaconda2 running smoothly on Eclipse's PyDev environment.
I have received a custom package from a colleague in the form of a folder with a "library" sub-directory that contains many ".pyc" files (which I presume are the function files) and a "init.py" file. But no matter what I do, I cannot seem to install the folder as a package.
I have tried everything posted here in the Anaconda Prompt (which I'm assuming was the correct way of implementing the instructions)
http://conda.pydata.org/docs/using/pkgs.html#install-non-conda-packages
but nothing worked.
I am very new to really working with Anaconda, Python, Eclipse, and PyDev (I have only written simple scripts with the default IDLE IDE in the past).
All I really want to be able to do is to use the package of functions given to me - even if they are not properly "installed", although that would be ideal. If anyone out there can help me with this I would be very grateful!
Pyc are precompiled files, you dont need them.
You should simply import package folder with
import folder-name
I want to install python on a flash drive in a virtual environment so that I can develop code wherever I am. Is this possible to do in such a way that I can use my flash drive on windows/mac/linux computers?
For windows, head to Portable Python (http://PortablePython.com) to see various options you have,
For linux and Mac you don't need to install it on USB drive as those systems usually come with Python pre-installed. If you need specific packages for those systems, bring them on USB together with a command line script that can load them with one call in virtualenv on those systems and you are good to go !
Be aware that this is never 100% bullet proof as you are depending on Python version you are using/bringing packages for.
You could try looking at setting up something using some VirtualEnv type environments, with the various Python versions installed on your machines.
Not sure how you'd get round the different paths on the different operating systems though.
Virtualenv: http://pypi.python.org/pypi/virtualenv
As #millimoose pointed out, you could install three different versions of Python.
For each Python package you are working on, you can create a .pth file in the site-packages directory of each Python version that you would like to use the package from.
Note that, as described here:
If you put a .pth file in the site-packages directory containing a path, python searches this path for imports.
For example, if you have a package named my_package that you are working on that resides at the path C:\Users\Me\Documents\dev_packages\my_package, you can add a file with extension .pth (note that the name doesn't matter, specifically it doesn't have to have any relation to the package name), with the contents:
C:\Users\Me\Documents\dev_packages
This will add C:\Users\Me\Documents\dev_packages to the Python import search-path, causing the my_package package to be discovered. By placing this .pth file in the site-packages directory of each Python version, my_package will be available in all corresponding versions of Python.
In continuing to research a solution for this question on ServerFault:
https://serverfault.com/questions/221203/mercurial-hook-fails-on-windows
I discovered an interesting and somewhat disturbing thing: I have seem three different versions of Python on my machine (four if you count the "official" version which doesn't appear to have a DLL with it....). Here's shot from my file search tool:
More Info:
I am running Windows 7 64-bit
Both the TortoiseHG and the Mercurial directories are on my path, with the Mercurial directory listed first.
I have Python 2.6 installed in c:\Python26
I have no entry for any type of PYTHON-based environmental variable. (Should I?)
I suspect that this is the source of the my problem from the question above, but I thought I'd ask here, as this is particular issue is a Python deal.
I tried to replace both DLLs with each other, but when I use the one that comes with Mercurial, then TortoiseHg stops working.
It seems to me that "there should only be one" Python on my machine. How do I achieve that?
For the problem that you mentioned earlier, the mercurial package got installed within python under mercurial home but you are executing scripts under C:\python26. So you need to install and execute your script under mercurial python
As seth mentioned earlier it is perfectly ok to multiple python homes in the same machine but you just to pay attention when installing python libraries to make sure that you are under the right home which means you set the path right before calling python.
Side note: The Python installation in "C:\Python26" installs its DLL to the Windows directory, in your case "C:\Windows\SysWOW64".
Answering your serverfault question: As you installed Mercurial as standalone version, you'll have to place any packages that are accessed by hooks into Mercurial's library folder (if it has one, could also be "library.zip").
I would recommend you to uninstall the Mercurial standalone version and instead install Mercurial with pip. This makes updates easier and you can use your normal "site-packages" directory for both normal Python libraries and hg hooks.
I would assume that tortoise/mercurial have just embedded their own versions of python to do whatever they need to do.
I wouldn't worry about it, the DLLs won't stomp on each other -- the PATH is the last placed that windows searches to find DLLs.
See: http://msdn.microsoft.com/en-us/library/7d83bc18(v=vs.80).aspx
Each DLL is for that application. There is only one in your search path so you don't need to worry about conflicts.
Is something not working that prompted you to worry about this??
Your assumption that there should only be one is wrong, each application has bundled a specific version with a fixed API, you can't just drop another in and hope it'll work.
The Python DLL naming structure only provides the major version and revision numbers. You are probably looking at the DLLs for versions 2.6.1, 2.6.4, 2.6.5, and 2.6.6.
All of this doesn't really matter as long as each application contains its own copy of the python26.dll. Windows will not explore the PATH environment variable if there is a local copy of the file.