I am relatively new to programming&C++ and just began learning about MYSQL. I have been searching for a couple of days but couldn't find a solution. I usually use Cygwin&VIM&g++ to write, compile and run codes that I write.
My goal is to retrieve data from MYSQL database that I've set up on my laptop and be able to run a simple algorithm on that data and possibly update the database.
I went into MYSQL's website and went through tutorials and found an example here. I have Boost, Connector, MYSQL server lib downloaded. When I run it, I get an error saying 'connection.h' was not found. I'm sure this is because when I compile it, g++ does not have the location of the library added to the search path that it goes through. The example has something like:
#include <cppconn/conneciton.h>
where these angled brackets means it is going to search (after the current directory) the standard search directory. I am guessing I have to add a new path (the location of where the libraries are) so that the compiler looks at that standard directory and compiles the header.
Through googling I am thinking in g++ I can use -Ldir -I to add a new search path but I don't get how to use it. Can anyone kindly explain/show me (by example) how to get over with this problem? :(
An #include issue would be solved with -I (-L is for a library if it is needed but first you have to get through the compile).
You need to figure out where the headers were installed (likely somewhere under either /usr/include or /usr/local/include/), and then add a -I with that directory, it may also be that you need to install a development package, many *nix distributions split based on runtime-build time distinctions.
And note also with the -I that the package may do something like install to /usr/include/libraryname/libname_version/libname in such a case you would only want to add -I/usr/include/libraryname/libname_version/ and then in your source file have #include
I use Stata 14.1 on Windows 8.1 and moved my personal .ado files to GitHub repositories. This put foo.ado in "C:/Users/Richard/Documents/GitHub/foo/", bar.ado in "C:/Users/Richard/Documents/GitHub/bar/", and so on.
I added the GitHub root directory to adopath with adopath + "C:/Users/Richard/Documents/GitHub/", but Stata did not search "foo", "bar", and other sub-directories for .ado files. I fixed this by adding the foo.ado repository with adopath + "C:/Users/Richard/Documents/GitHub/foo", and so on.
I expected Stata to search "C:/Users/Richard/Documents/GitHub/" recursively because it does so for BASE, SITE, and PLUS. Is recursive searching limited to the default adopath directories?
To be fair, it isn't difficult to add a ten directories to adopath, but I want to follow best practices. I can't find much about adopath other than help adopath and this 1996 FAQ.
Stata doesn't exactly recursively search BASE, SITE, and PLUS. It searches each directory, and within the directory, will search in exactly one subdirectory having as its name the first letter of the command being searched for.
Within PERSONAL, I created the subdirectory f and placed within it foo.ado. When I typed the command foo into Stata's Command window, Stata found foo.ado and ran the program within.
This doesn't directly solve your problem, but it does show that Stat treats PERSONAL consistently with the other directories, reducing the likelihood of convincing StataCorp to implement your suggestion, but confirming that your workaround seems to be "best practices" such as they are.
On my Mac, I renamed the directory f to gnxl and then, in a terminal window
cd ~/Library/Application Support/Stata/ado/personal
ln -s gnxl/foo.ado .
after which, having exited and relaunched Stata, the foo command performed as expected. Perhaps this points a direction for you, with some automation to generate the symbolic links as new ado files are created in your repository. I don't know enough GitHub to know if that is possible within its framework.
The title of this question does not begin to capture my years of exasperation with the RPM system. There is a vast gulf between a development system (./configure; make; make install;) and a rpm system (tar files, patch files, spec files, arcane build scripts, environments and tools) which I cannot bridge.
All I want to do is to change a few lines of code in a bigger program.
The problems which I run into:
Getting the source code of the system as-installed (e.g. SRPM from EPEL, original tarball, something else). What source should I use?
Getting that source code into a ready-to-edit form - something that I can edit with my favourite editor. How can I know that I'm editing the code as-deployed, bugs and all? (rpm -ivh x.src.rpm gives me tar files and squabs of patch files littered about in the SOURCES directory ... how can I get it right?)
Editing the code to implement some amazing hack (this part I can actually do).
Compiling the amazing code as edited - just compiling it in-place. Usually I can get this right, but it would be nice to have a hand sometimes, e.g. with ./configure set to use something other than the default /usr/local and /lost+found/opt/etc/opt or whatever crazy default autoconf decides to use.
Transforming my edits into a patch against the previous source and building new RPMs to test on some remote system (this is the great promise of RPM - pristine sources and hacky patches). If I do a diff of the original and the edited directories, the resulting patch contains all sorts of rubbish that I don't want to delete because I'm still developing (e.g. object code). (Actually, I don't have an 'original' at this point to do a diff against ... because I was only looking at the code casually when I realised I could "improve" it ...) Should I use some revision control system to track the changes I am making?
This should be simple stuff, but somehow all I can do is edit the code. After I have edited the code, it can never get over the hump, even though it is an already-solved problem. I have a GREAT fix for an open source project, but every single time that I finish developing my amazing hack, having delved into the code and made it compile (and possibly work), I am completely stumped. Nothing at all can turn my modified and now amazing source tree into a RPM. I end up deploying source code (into /usr/local), because that at least works.
How do people who do (say) security fixes actually go about the extract-edit-compile-test loop?
The SRPM is (relatively) self-contained: there are often some assumptions about build requirements not reflected in the spec file.
I would start by taking the SRPM, and rebuilding it to address the issue of build-requirements (adding whatever is needed to get it to build).
Then, extract the spec-file and sources from the SRPM, putting the patches and tar-file(s) into ~/rpmbuild/SOURCES, and building from the spec-file
Next, modify the spec-file to add my own patch file (or scripting changes),
Finally there's a new SRPM with my changes.
For extracting, I use an unrpm script (essentially a wrapper around cpio) which can be found on the network.
Making your own patch file is discussed here:
HowTo Create A Patch File For A RPM
RPM - Creating Patches
Patches for .spec file
I am trying to find a way to call notepad++ from command line with compare plugin showing the compare result providing I pass 2 files name which I want to compare.
Think like I have a batch file, which does some work and result is opening notepad++ showing 2 files in compare mode. (Yes, compare plugin is installed)
If anyone has any other suggestion to using any other editor or software also welcome..
tl;dr:
The command is Notepad++\plugins\ComparePlugin\compare.exe file1 file2.
Details:
Download the compare plugin https://bitbucket.org/uph0/compare/downloads/ComparePlugin.v1.5.6.6.bin.zip. Installing the compare plugin from the plugin manager within Notepad++ does not install the requisite exe. I assume you could also build from source to obtain the exe.
Follow the manual installation instructions in the readme:
To install manually, copy ComparePlugin.dll and ComparePlugin subfolder
into the plugins directory C:\Program Files\Notepad++\Plugins.
For a portable Notepad++ installation, you need to run the command from a directory above the notepad++ directory (or with absolute path of exe), otherwise you get an error that Notepad++.exe is not found.
The commands look like this:
>cd C:\portapps\Notepad++
>cd ..
>Notepad++\plugins\ComparePlugin\compare.exe C:\files\file1.txt C:\files\file2.txt
ufo's answer put me on the right track but it did not contain the commands to run.
There's a tool called NppCompareLoader doing exactly what you want. Simply drop it in the N++ installation folder. I'm using it since many years as a diff viewer for TortoiseSVN and TortoiseGit, thus you should certainly be able to call it right from command line.
/EDIT
Since the (unofficial) Compare-plug-in version 1.5.6.6 the additional loader mentioned above isn't required anymore. There's already one included in the plug-in. Here's the regarding change-log fragment:
NEW: Loader for using N++ as an external diff viewer (e.g. in TortoiseSVN, TortoiseGit, ..)
I am attempting to put together a simple c++ test project that uses an embedded python 3.2 interpreter. The project builds fine but Py_Initialize raises a fatal error:
Fatal Python error: Py_Initialize: unable to load the file system codec
LookupError: no codec search functions registered: can't find encoding
Minimal code:
#include <Python.h>
int main (int, char**)
{
Py_Initialize ();
Py_Finalize ();
return 0;
}
The OS is 32bit Vista.
The python version used is a python 3.2 debug build, built from sources using VC++ 10.
The python_d.exe file from the same build runs without any problems.
Could someone explain the problem and how to fix it? My own google-fu fails me.
EDIT 1
After going through the python source code I've found that, as the error says, no codec search functions have been registered. Both codec_register and PyCodec_Register are as they should be. It's just that nowhere in the code are any of these functions called.
I don't really know what this means as I still have no idea when and from where these functions should have been called. The code that raises the error is entirely missing from the source of my other python build (3.1.3).
EDIT 2
Answered my own question below.
Check the PYTHONPATH and PYTHONHOME environment variables and make sure they don't point to Python 2.x.
http://bugs.python.org/issue11288
Parts of this have been mentioned before, but in a nutshell this is what worked for my environment where I have multiple Python installs and my global OS environment set-up to point to a different install than the one I attempt to work with when encountering the problem.
Make sure your (local or global) environment is fully set-up to point to the install you aim to work with, e.g. you have two (or more) installs of, let's say a python27 and python33 (sorry these are windows paths but the following should be valid for equivalent UNIX-style paths just as well, please let me know about anything I'm missing here (probably the DLLs path might differ)):
C:\python27_x86
C:\python33_x64
Now, if you intend to work with your python33 install but your global environment is pointing to python27, make sure you update your environment as such (while PATH and PYTHONHOME may be optional (e.g. if you temporarily work in a local shell)):
PATH="C:\python33_x64;%PATH%"
PYTHONPATH="C:\python33_x64\DLLs;C:\python33_x64\Lib;C:\python33_x64\Lib\site-packages"
PYTHONHOME=C:\python33_x64
Note, that you might need/want to append any other library paths to your PYTHONPATH if required by your development environment, but having your DLLs, Lib and site-packages properly set-up is of prime importance.
Hope this helps.
The core reason is quite simple: Python does not find its modules directory, so it can of course not load encodings, too
Python doc on embedding says "Py_Initialize() calculates the module search path based upon its best guess" ... "In particular, it looks for a directory named lib/pythonX.Y"
Yet, if the modules are installed in (just) lib - relative to the python binary - above guess is wrong.
Although docs says that PYTHONHOME and PYTHONPATH are regarded, we observed that this was not the case; their actual presence or content was completely irrelevant.
The only thing that had an effect was a call to Py_SetPath() with e.g. [path-to]\lib as argument before Py_Initialize().
Sure this is only an option for an embedding scenario where one has direct access and control over the code; with a ready-made solution, special steps may be necessary to solve the issue.
Ran into the same thing trying to install brew's python3 under Mac OS! The issue here is that in Mac OS, homebrew puts the "real" python a whole layer deeper than you think. You would think from the homebrew output that
$ echo $PYTHONHOME
/usr/local/Cellar/python3/3.6.2/
$ echo $PYTHONPATH
/usr/local/Cellar/python3/3.6.2/bin
would be correct, but invoking $PYTHONPATH/python3 immediately crashes with the abort 6 "can't find encodings." This is because although that $PYTHONHOME looks like a complete installation, having a bin, lib etc, it is NOT the actual Python, which is in a Mac OS "Framework". Do this:
PYTHONHOME=/usr/local/Cellar/python3/3.x.y/Frameworks/Python.framework/Versions/3.x
PYTHONPATH=$PYTHONHOME/bin
(substituting version numbers as appropriate) and it will work fine.
From python3k, the startup need the encodings module, which can be found in PYTHONHOME\Lib directory.
In fact, the API Py_Initialize () do the init and import the encodings module.
Make sure PYTHONHOME\Lib is in sys.path and check the encodings module is there.
I had this issue with python 3.5, anaconda 3, windows 7 32 bit. I solved it by moving my pythonX.lib and pythonX.dll files into my working directory and calling
Py_SetPythonHome(L"C:\\Path\\To\\My\\Python\\Installation");
before initialize so that it could find the headers that it needed, where my path was to "...\Anaconda3\". The extra step of calling Py_SetPythonHome was required for me or else I'd end up getting other strange errors where python import files.
I just ran into the exact same problem (same Python version, OS, code, etc).
You just have to copy Python's Lib/ directory in your program's working directory ( on VC it's the directory where the .vcproj is )
There appears to be something going wrong with the release build either failing to include the appropriate codecs or else misidentifying the codec to use for system APIs. Since the python_d executable is working, what does that return for os.getfsencoding()? (Use the C API to call that between your Initialize/Finalize calls)
I had the same issue and found this question. However from the answers here I was not able to solve my problem. I started debugging the cpython code and thought that I might be discovered a bug. Therefore I opened a issue on the python issue tracker.
My mistake was that I did not understand that Py_SetPath clears all inferred paths.
So one needs to set all paths when calling this function.
Link to the issue conversation
For completion I also copied the most important part of the conversation below.
My original issue text
I compiled the source of CPython 3.7.3 myself on Windows with Visual Studio 2017 together with some packages like e.g numpy. When I start the Python Interpreter I am able to import and use numpy. However when I am running the same script via the C-API I get an ModuleNotFoundError.
So the first thing I did, was to check if numpy is in my site-packages directory and indeed there is a folder named numpy-1.16.2-py3.7-win-amd64.egg. (Makes sense because the python interpreter can find numpy)
The next thing I did was to get some information about the sys.path variable created when running the script via the C-API.
#### sys.path content ####
C:\Work\build\product\python37.zip
C:\Work\build\product\DLLs
C:\Work\build\product\lib
C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\PROFESSIONAL\COMMON7\IDE\EXTENSIONS\TESTPLATFORM
C:\Users\rvq\AppData\Roaming\Python\Python37\site-packages
Examining the content of sys.path I noticed two things.
C:\Work\build\product\python37.zip has the correct path 'C:\Work\build\product\'. There was just no zip file. All my files and directory were unpacked. So I zipped the files to an archive named python37.zip and this resolved the import error.
C:\Users\rvq\AppData\Roaming\Python\Python37\site-packages is wrong it should be C:\Work\build\product\Lib\site-packages but I dont know how this wrong path is created.
The next thing I tried was to use Py_SetPath(L"C:/Work/build/product/Lib/site-packages") before calling Py_Initialize(). This led to
Fatal Python Error 'unable to load the file system encoding'
ModuleNotFoundError: No module named 'encodings'
I created a minimal c++ project with exact these two calls and started to debug Cpython.
int main()
{
Py_SetPath(L"C:/Work/build/product/Lib/site-packages");
Py_Initialize();
}
I tracked the call of Py_Initialize() down to the call of
static int
zipimport_zipimporter___init___impl(ZipImporter *self, PyObject *path)
inside of zipimport.c
The comment above this function states the following:
Create a new zipimporter instance. 'archivepath' must be a path-like
object to a zipfile, or to a specific path inside a zipfile. For
example, it can be '/tmp/myimport.zip', or
'/tmp/myimport.zip/mydirectory', if mydirectory is a valid directory
inside the archive. 'ZipImportError' is raised if 'archivepath'
doesn't point to a valid Zip archive. The 'archive' attribute of the
zipimporter object contains the name of the zipfile targeted.
So for me it seems that the C-API expects the path set with Py_SetPath to be a path to a zipfile. Is this expected behaviour or is it a bug?
If it is not a bug is there a way to changes this so that it can also detect directories?
PS: The ModuleNotFoundError did not occur for me when using Python 3.5.2+, which was the version I used in my project before. I also checked if I had set any PYTHONHOME or PYTHONPATH environment variables but I did not see one of them on my system.
Answer
This is probably a documentation failure more than anything else. We're in the middle of redesigning initialization though, so it's good timing to contribute this feedback.
The short answer is that you need to make sure Python can find the Lib/encodings directory, typically by putting the standard library in sys.path. Py_SetPath clears all inferred paths, so you need to specify all the places Python should look. (The rules for where Python looks automatically are complicated and vary by platform, which is something I'm keen to fix.)
Paths that don't exist are okay, and that's the zip file. You can choose to put the stdlib into a zip, and it will be found automatically if you name it the default path, but you can also leave it unzipped and reference the directory.
A full walk through on embedding is more than I'm prepared to type on my phone. Hopefully that's enough to get you going for now.
I had the problem and was tinkering with different solutions mentioned here. Since I was running my project from Visual Studio, apparently, I needed to set the environment path inside Visual Studio and not the system path.
Adding a simple PYTHONHOME=PATH\TO\PYTHON\DIR in the project solution\properties\environment solved the problem.
For me this happened when I updated Python 64 bit from 3.6.4 to 3.6.5. It threw some error like "unable to extract python.dll. Do you have permissions."
Pycharm also failed to load interpreter, even though I reloaded it in settings. Running python command gave same error, with and without administrator mode.
Reason
There was error in installation of Python, include folder in python installation directory C:\Users\USERNAME\AppData\Local\Programs\Python\Python36 was missing
Reinstalling Python also dint solve the issue.(Not removal and install)
Solution
Uninstall Python and Install of Python again.
Because running installer was just extracting same files excluding include folder
In my cases, for windows, if you have multiple python versions installed, if PYTHONPATH is pointing to one version the other ones didn't work. I found that if you just remove PYTHONPATH, they all work fine
For those working in Visual Studio simply add the include, Lib and libs directories to the Include Directories and Library Directories under
Projects Properties -> Configuration Properties > VC++ Directories :
For example I have Anaconda3 on my system and working with Visual Studio 2015 This is how the settings looks like (note the Include and Library directories) :
Edit:
As also pointed out by bossi setting PYTHONPATH in your user Environment Variables section seems necessary.
a sample input can be like this (in my case):
C:\Users\Master\Anaconda3\Lib;C:\Users\Master\Anaconda3\libs;C:\Users\Master\Anaconda3\Lib\site-packages;C:\Users\Master\Anaconda3\DLLs
is necessary it seems.
Also, you need to restart Visual Studio after you set up the PYTHONPATH in your user Environment Variables for the changes to take effect.
Also note that :
Make sure the PYTHONHOME environment variable is set to the Python
interpreter you want to use. The C++ projects in Visual Studio rely on
this variable to locate files such as python.h, which are used when
creating a Python extension.
So, for some reason the python dll fails to locate the encodings module. The python.exe executable apparently finds it because it has the expected relative path. Modifying the search path works.
The reason for all of this? Don't know but at least it works. I highly suspect a typo on my part somewhere, that's usually the reason for odd bugs it seems.