I took a fully working Xcode project and added a Podfile to it. After doing the pod install, opening the newly created workspace and trying to build, it no longer works. When I compile now I get errors from a couple system header files. For example, NSFetchRequestExpression.h tells me:
Attempting to use the forward class 'NSExpression' as superclass of 'NSFetchRequestExpression'
I manually went in and added $(inherited) to the front of the "Framework Search Paths" and "Other Linker Flags" build settings. Any ideas on what I need to change to make this work?
Finally figured this out. CocoaPods actually changes the way includes work. I had a core data entity called Time, which creates and NSManagedObject subclass called Time.h. When CocoaPods mucks with the header include search paths, suddenly the system files which asked for found my time file instead. I renamed that class (which I shouldn't have had to do!) and now everything works fine.
Related
I'm working on my second application in QT and i'm trying to deploy a rough copy for testing. It would not run on a test computer, runs with no problems on mine, giving the error "Procedure Entry Point _ZdaPVJ not found in QT5core.dll". So to make sure that was not my program messing things up, i created a blank test application, compile it for release, moved the test.exe to a different location, run windeployqt --release test.exe, it created all the dependencies and folders. clicked on test.exe run with no problem. grabbed the folder recently created took it to the other computer and go the same error.
Is there something that i have forgotten since i compile my first application? Did i changed some setup somewhere without realizing it?
frustrated...
Perhaps you can check if your problem is related to different versions of the dll existing on your system and the wrong one is being loaded:
QT Release build DLL procedure entry point error
https://forum.qt.io/topic/26707/the-procedure-entry-point-cound-not-be-located-in-the-dynamic-link-library
As is suggested in the latter link above (towards the bottom), you could try to use dependency walker to determine from where the dll is loaded. Or use static linking with the licensing issues that causes (also see the latter link above).
And throwing in a final link on using Qt's Window's Deployment tool: Qt deployment; the procedure entry point ... could not be located
Am new to Xamarin and is currently building a very simple app using the tutorial from Youtube. Am just in a middle of the video when I got this error even tho I carefully followed all instructions. And even the instructor in the video was able to run his app successfully
Here's the code where I'm getting the error:
var view = inflater.Inflate(Resource.Layout.SignUp, container, false);
For me it is caused by namespace changes. After I corrected the namespace in project properties, then I can build again
I just deleted my newly created axml file, rebuild, add it again, and this time, clean and rebuild.
Everytime I added a new axml file, I clean and rebuild. That's all, thank you :).
Actually this problem occurs when your ResourceDesigner.cs file has not yet mapped the file that you added to your resource directory.
The easiest way i would suggest to handle this situation is you comment the code you are trying to write and clean build your project and it will work like a charm.
Good luck!
In my Resource.Layout.toolbar, Resource was ambiguous between Android.Resource and Xamarin.Forms.Platform.Android.Resource. Instead the one that works for me is [Project name].Droid.Resource. Clean, deleted bin/debug and now it's fine
Resource.designer.cs was excluded from project. Solved by including back.
In Xamarin.Android this problem can be resolved by saving other axml/xml file. Many times cleaning solution, deleting bins/obj doesn't working for me.
In my case my Main file was configured in the Build Action as AndroidResourceAnalysisConfig and then change property to AndroidResource then Build my project and it works.
I had a lot of "XXX" does not contain "XXX" errors like this after a git reverse operation. Very annoying.
I tried all the solutions I could find, all without luck. Finally I magically fixed it by going to the Android project properties, Android Options, then unchecked "Use Fast Deployment (debug mode only)". I then built the project and it worked. Then I went back and checked that option so it was back to normal, and everything is fine.
I am trying to create a project assosiated with the SimConnect SDK.
I am new to QT, and in Visual Studio, I just had a SimConnect.h file, a .lib file, and a .dll file, and I managed to make it work. Now I am trying to create a C++ widget project, using the same SDK, but in QT.
I put the header file in my QT project's folder, where the other default code and header files are located, and then I went to the project and added them as existing files, as I read in Google. I'm having problems with the actual library.
I've been searching Google for a guide on how to add a library file to the project, I did some things I saw on the internet, like the LIBS line for example, but I probably did it wrong, even though it looked very simple.
I am not sure where to drop my dll/library files in the project directory, maybe the problem is I always put them in the wrong spot.
The furthest I got to, was an error message saying "Unresolved external symbol", and a red writing saying ".obj file not found" on every function I tried to use from the SimConnect functions, which probably means QT couldn't find my library/dll file.
I also tried to add the libraries from the "Add library" option in the project, but that didn't work too.
EDIT: it also warns "warning: LNK4272: library machine type 'X86' conflicts with target machine type 'x64'" maybe it has to do something with it.
(Posted on behalf of the OP).
Solved! My problem was my machine was set to 64bit, while the library was set to 32bit, so I downloaded the 32bit kit, and ran the project through that, and it worked!
I'm attempting to figure out how to use Libraries in Xcode following this tutorial. Everything seems straightforward up to the point of adding the target dependencies. Whenever I click "+" to add a target dependency in "Build Phases", my project briefly flashes into view then disappears behind a view that says "No Filter Results".
There are no white spaces in my project directory tree all the way back to root. I'm using Xcode 4.6.1. I've tried typing my project name in the search pane and adding the files to my project a bunch of different ways, all with the same results. Is this a known bit of weirdness in Xcode or am I doing something wrong?
This question is a bit old, but I just stumbled on the same problem. Xcode's navigator was displaying "No filter results" instead of the project structure. I closed Xcode and re-opened and this did not solve the problem.
What solved was to go to Navigate > Reveal in Project Navigator. After this, the structure appeared again.
Eventually figured this out on my own. The solution, when Xcode gets into this state, is to close it and restart and adding target dependencies works as expected.
This problem remains at Xcode 11.1 .
I used another approach, I've been deleting my source project .xcworkspace, after that is just use the pod commands: pod deintegrate and pod install; Open your "new .xcworkspace". It's done !
You don't need commit any new thing that will show up on git status (.project or whatever), discard if you wish and lets code!
I'm trying to access a MySql database from a Qt application but I get the following error:
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QSQLITE2
I find this very strange cause I have libqsqlmysql.so on my Qt folder. I have even tried to compile the MySql driver as a static plugin and add it to my .pro file as:
QTPLUGIN += qsqlmysql
But this also generates the same runtime error (it must've found the plugin cause there's no error compiling the application)
What am I missing? I would like to avoid having to compile Qt from source cause this will have to work seamlessly on the deploy machines as well.
BTW: Even though I'm developing and testing on Linux I will need to support Windows. Will I experience this same issue on Windows? How can I compile and link the MySql driver in both Linux and Windows?
The solution:
After following #Sergey's recommendations I did an strace of the application redirecting the output to grep so I could search for 'mysql' and for my surprise the application wasn't looking for the plugin at QTDIR/plugins/sqldrivers where I had libqsqlmysql.so, it was looking at QTDIR/lib. After copying the plugin to the lib folder the MySql connection worked.
Try opening the shared library with dlopen() and see if it loads and if not, what dlerror() tells you. I always run into similar problems on Windows. LoadLibrary()/GetLastError() saved me numerous times (last time it was because of a wrong version of some libiconv/libintl DLL). Running ldd on the plugin may also help.
If dlopen() works fine, try to load the plugin with QPluginLoader. If it doesn't load, then check the buildkey of the plugin. I usually do it the dirty way by running strings on the plugin and then looking for strings like "buildkey" or "QT_PLUGIN_VERIFICATION_DATA". Just looking at the build key and around it may give you an idea. For example, you may realize that you have compiled your plugin in the release mode while your application is compiled in the debug mode. In such case the build key won't match and the plugin won't load. Everything in the build key must match your configuration. Note that the version and the build key are checked differently: the build key must match exactly (or match some black magic called QT_BUILD_KEY_COMPAT), but in the version only the major version must match exactly, the minor version must be the version of Qt the plugin was compiled with or later and the patch level is ignored. So if your plugin was compiled with Qt 4.x.y then it will work with Qt versions 4.z.* where z>=x. This actually makes sense.
If the build key looks okay (which is unlikely if you got to this point), you may wish to look at QLibraryPrivate::isPlugin() source code to figure out what's wrong, but that doesn't look like an easy task to me (although running this in a debugger may help).
If QPluginLoader does load the plugin, check if it is in the right directory and has correct permissions. If you still didn't solve the problem by this point, it's time to look at the SQL module source code that actually loads these plugins. But it is extremely unlikely. I ran into this problem many, many times and it was always either the library not loading or the build key not matching.
Another way to go after QPluginLoader loads the plugin successfully is to use strace to figure out whether the program at least tries to open the plugin file. Searching for something like "sqldrivers" or "plugins" in the strace output should also give away the directory where Qt is searching for its plugins and specifically SQL drivers.
Update
Is it possible to compile the driver as a static plugin and don't worry about anything? Let's try:
d:\Qt4\src\plugins\sqldrivers\psql>qmake CONFIG+=static LIBS+=-Ld:/programs/Post
greSQL/lib INCLUDEPATH+=d:/programs/PostgreSQL/include
d:\Qt4\src\plugins\sqldrivers\psql>make
It compiles fine and now I got libqsqlpsql.a (release) and libqsqlpsqld.a (debug) in QTDIR/plugins/sqldrivers (it is the right place on Windows). I am using PostgreSQL driver here, but I don't think it will be any different for MySQL which I just don't have installed. Ok, let's compile some real program with it:
d:\alqualos\pr\archserv>qmake QTPLUGIN+=qsqlpsql PREFIX=d:/alqualos LIBS+=-Ld:/g
nu/lib INCLUDEPATH+=d:/gnu/include LIBS+=-Ld:/programs/PostgreSQL/lib LIBS+=-lpq
Note that I had to manually link to libpq, otherwise the linker would complain about undefined references. The funny thing is, qmake knows that qsqlpsql is located in QTDIR/plugins/sqldrivers and sets compiler and linker options accordingly. So it still needs to be in the right place to work, only you don't have to worry about your users running into the same problem as it is only used during compilation. An alternative would be to just use LIBS+=-Lpath/to/plugin LIBS+=-lqsqlpsql instead of QTPLUGIN+=qsqlpsql, at least the docs say that it should work, but I haven't tested it.
In order for the application to actually use the plugin I had to put the following in my main unit (CPP file):
#include <QtPlugin>
Q_IMPORT_PLUGIN(qsqlpsql)
It works! Also, from what I've been able to figure out from the sources, the build key and the version are checked only when a plugin is dynamically loaded (all the relevant stuff is in the QLibrary's private class, not even QPluginLoader's). So the resulting executable may (or may not, depending on the binary compatibility) work even with different versions and builds of Qt, although using it with older versions may trigger some bugs that were fixed later.
It is also worth noting that the order for loading SQL drivers is this: use the driver statically linked into Qt if available, then look for a driver registered manually with QSqlDatabase::registerSqlDriver(), then look for a driver statically imported into the application (the way described above), and finally try to load a shared plugin. So when you link statically, your users won't be able to use dynamically linked drivers they may already have, but will be able to use drivers linked statically into Qt (like in Ubuntu).
I compiled QT first and then realised that I need mysql as well. So I compiled mysql plugin by
executing following command in QT-DIR\src\plugins\sqldrivers\mysql folder.
Mysql plugin compile command
qmake "INCLUDEPATH+=$$quote(C:\Program Files\MySQL\MySQL Server 5.5\include)" "LIBS+=$$quote(C:\Program Files\MySQL\MySQL Server 5.5\lib\libmysql.lib)" mysql.pro
Plugings are then created in created in folder QT-DIR\plugins\sqldrivers.
However, when I tried to use it in my code. It failed with following error.
Error msg
QSqlDatabase: QMYSQLDriver driver not loaded
Solution
After some googling and checking Path variable I realised that the Mysql server lib
( C:\Program Files\MySQL\MySQL Server 5.5\lib) directory was not in my Path variable. I expect that the dll in this folder are used by the plugin at runtime. After including Mysql server lib in Path variable everything worked smoothly. Hope this information saves some hair on other programmers scalp, as I uprooted quite a few. :D
Last time I looked at this you needed to rebuild Qt from source and include the appropriate MySQL source.
Building Qt from the sources is not hard, it just takes a while. You are likely to have the required tools already.
A possible workaround may be to access the back-end over ODBC instead.
In order for your app to pick up the plugin at runtime, the shared library implementing the MySQL plugin needs to be placed in the correct directory. The best way of determining that directory is to check the output of QCoreApplication::libraryPaths. You can also force specific paths by using a qt.conf file.
Please note that plugins must be placed in subdirectories within the plugin path, and the final part of the path name (i.e., the parent directory of the shared libraries) cannot be changed. SQL drivers need to go in a directory named sqldrivers, i.e. <pluginpath>/sqldrivers. For more details on plugin directories, see How to Create Qt Plugins.
I was experiencing this same issue as well. I've been installing and experimenting with a lot of different Python tools and UIs. I then uninstalled everything python related. I did a fresh install of Python 3.2, PyQT 3.2, and Eric5. No more errors with the QMySQL driver.
well i have had this issue, and after a lot of time, and different tools, i found that QT ( on windows, have not been able to test on Linux.) loads the "QSQLMYSQL.." when requested, but before runtime the lib ("QSQLMYSQL..") file must reside on one of the searched paths (QApp.libraryPaths()) inside a folder called "sqldrivers".. otherwise QT will just ignore the file, even if it is at some other point inside the searched path.
what i did was to monitor the dependency of a sample app, and when i removed the "QSQLMYSQL.." dll from "plugins\sqldrivers\" it failed, but when i maded a folder inside the app folder, called "sqldrivers" and placed the "QSQLMYSQL..." inside there, it loaded.
what i have is mysql 5.5, qt 4.7.4.
hope anyone can use this, and if anyone knows more about it, i would like to know where to find it(http://doc.qt.nokia.com/stable/sql-driver.html, is the closest you can get to the information about the folder structur). :P
This may also happen if your QMYSQL plugin is linked against the "wrong" mysql_client.a or it isn't in the LD_LIBRARY_PATH. I had this problem on OSX because mysql was installed via ports, and I fixed it with:
install_name_tool -change libmysqlclient.18.dylib /usr/local/mysql/lib/libmysqlclient_r.18.dylib libqsqlmysql.dylib