I'm not sure why this is, but 99% of the problems I have with programming in C++ have to do with the gcc linker.
I want to link the Qt library to a project in CodeLite. This is the code I have so far:
#include <QApplication>
int main(int argc, char *argv[])
{
return 0;
}
When I compile, I get the error
/Users/andrew/Dev/C++/COSC 102/elitecod/main.cpp:1:24: error: QApplication: No such file or directory
I have Qt installed (with Homebrew, Mac OS X Lion) in /usr/local/include. Why is this happening, and how can I fix this problem?
The error indicates it can't find the file QApplication. You need to add the Qt 'include' directory to the list of places the compiler should look for it and other header files.
A brief google seems to indicate you may have other problems with Qt, you might want to keep this link handy.
Related
I want to use gstreamer library for video programming and I read that Qt5.5.0 provided support for gstreamer-1.0, which is the library I use. I downloaded firstly version 1.0.7, but I got the following error, so I downloaded the latest version 1.5.2, which I am trying to use now.
I managed to link the gstreamer library header files, so I didn't build it, but just include its path and access the header files and libs. Anyway, now I have an error of The program has unexpectedly finished. When I try to debug it, I get the following error in a pop-up:
During startup program excited with code 0xc0000135.
On General Messages:
:1:24: Reading only version 1.1 parts.
:10:5: Expected only Component and ModuleApi object definitions.
I read many questions related to this error, but none helped, I think is an error with the gstreamer library, but may be a compiler/debugger error too, as I read in some threads.
I checked my PATH variable, as I also can not run the program outside Qt (by trying to run the .exe in debug folder of the build) - the error : library Qt5Cored.dll missing - and I found this paths:
C:\Qt\Qt5.5.0_Android\5.5\mingw492_32\lib;
C:\Users\user\Documents\build-GStreamer-test5-Desktop_Qt_5_5_0_MinGW_32bit-Debug;
C:\Qt\Qt5.5.0_Android\5.5\mingw492_32\bin;
C:\Qt\Qt5.5.0_Android\Tools\mingw492_32\bin;
C:\Windows\system32; C:\Windows; C:\Windows\System32\Wbem; C:\Windows\System32\WindowsPowerShell\v1.0;
C:\Program Files\Skype\Phone\ (I dont know why is this included, but it was there when I checked )
I am relatively new to Qt, and never encountered this error before. If you need any code:
.pro:
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = GStreamer-test5
TEMPLATE = app
SOURCES += main.cpp
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
INCLUDEPATH += C:/gstreamer/1.0/x86/include/gstreamer-1.0
C:/gstreamer/1.0/x86/lib/gstreamer-1.0/include
C:/gstreamer/1.0/x86/include/glib-2.0
C:/gstreamer/1.0/x86/lib/glib-2.0/include
LIBS += -L C:/gstreamer/1.0/x86/lib/ -lgstreamer-1.0
and .main:
#include "mainwindow.h"
#include <QApplication>
#include <QDebug>
#include <stdio.h>
#include "gst/gst.h"
void *__gxx_personality_v0;
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
const gchar *nano_str;
guint major, minor, micro, nano;
gst_init (&argc, &argv);
gst_version (&major, &minor, µ, &nano);
if (nano == 1)
nano_str = "(CVS)";
else if (nano == 2)
nano_str = "(Prerelease)";
else
nano_str = "";
// printf ("This program is linked against GStreamer %d.%d.%d %s\n", major, minor, micro, nano_str);
qDebug() << "This program is linked against GStreamer %d.%d.%d %s\n", major, minor, micro, nano_str ;
return a.exec();
Firstly, I had the error :
undefined reference to `__gxx_personality_v0' , but fixed it by adding *void __gxx_personality_v0; , although I don't know what excatly it is.
Its been three days I struggle with this problem. Any help appreciated, or maybe if you can help me by some code on how to access the header files and libs, or how the configuration of the debugger options / PATH must be.
I am using Qt5.5.0 for Android, for Windows I use MinGW 4.9.2 32 bit compiler and GNU gdb 7.8 as debugger.
Thanks in advance!
I had similar problems in my project that was using both Qt and Gstreamer.
The сause of "undefined reference to `__gxx_personality_v0'" error is that Qt and GStreamer for windows from official sites were built using different compilers and their libstdc++ libraries are not compatible - they are using different exception handling methods.
In fact, GStreamer is pure C library. The only component of it that was written in C++ is taglib library. If you will build this lib from sources using your MinGW compiler, and then replace it in the GStreamer folder, the problem of incompatibility will be solved.
In more detail you can read here: https://github.com/knowthelist/knowthelist.
I managed to solve the above problem. I had to include in the .exe folder (the build-debug folder) all the dlls included, so I tried to run the .exe from there, not run it from Qt, and some errors with dlls missing gave me the names of the dlls. I found some in my library bin folder and some downloaded, and now everything seems fine :)
I have a problem when I want to link a library to my Qt project.
When I try to include an external library (libnodave.lib) in Qt Creator and try to build it, the following error occurs.
main.obj:-1: Fehler: LNK2019: unresolved external symbol __imp_daveSetDebug referenced in function main
I'm pretty sure that I included all needed files in my project and the .pro file. I used the "Add Library" wizard to add the library.
After no success with Qt Creator, I created a minimal example with Visual Studio. When I include all the needed files to the VS project, I can build and run it without errors. So I think that there must be a problem with Qt Creator linking the library. I also tried the Qt-Visual-Studio-Add-in, but there, the same error occurs.
Here are my minimal examples with the library I want to include.
In the Visual Studio example, I added the library path, the include path, and the name of the library to the project properties. It works.
I hope you can help me with my problem.
EDIT:
I want to use the library to get some data from a S7-300 SPS device.
The following code is the minimal example from Qt Creator.
#include <QCoreApplication>
#include <QDebug>
#include <nodave.h>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
daveInterface *di;
daveSetDebug(daveDebugConnect); // Function of libnodave Library
qDebug() << "Hello World";
return a.exec();
}
This is the whole code from the Visual Studio minimal example.
#include "stdafx.h"
#include <nodave.h>
int _tmain(int argc, _TCHAR* argv[])
{
daveInterface *di;
daveSetDebug(daveDebugConnect);
printf("Hello World\n");
return 0;
}
The code is very small, so I don't think that there is an error inside.
That's why I think it must be a problem with the Qt linker or something like that.
EDIT:
My .pro file.
QT += core
QT -= gui
TARGET = qtminimal
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
win32: LIBS += -L$$PWD/../libnodave-0.8.5/win/ -llibnodave
INCLUDEPATH += $$PWD/../libnodave-0.8.5
DEPENDPATH += $$PWD/../libnodave-0.8.5
The problem was that the Qt project is 64bit and the library I want to include is only 32bit.
So I downloaded the 32bit version of Qt and now it works.
I found the mistake, when I tried to build only the minimal example with libnodave, without any 64bit Qt libraries.
By creating a new Qt project in VS2013, with this workaround and adding the libnodave library afterwards I could change whether it should be a 64bit or 32bit build. By choosing the 32bit build, the Qt library creates errors but not the libnodave lib. When I choose 64bit build, only libnodave creates the errors.
I hope it is useful for someone else.
It's been days searching for a way to get the MySQL C API working with a MinGW compiler, and frankly I have to say this is getting very frustrating.
I'm trying to compile the minimal example:
#include <my_global.h>
#include <mysql.h>
int main(int argc, char **argv)
{
printf("MySQL client version: %s\n", mysql_get_client_info());
exit(0);
}
and I keep on getting:
[Linker Error] undefined reference to `mysql_get_client_info#0'
I have compiled the libraries (including libmysql.a which contains mysql_get_client_info) and properly linked them, included all include and lib directories properly. Basiacly, everything is done by the letter according not only to the tutorials but also to forum posts which dealt specifically with this problem.
Now, what am I doing wrong?
Thanks
Having looked at your make-file, it would appear you've forgotten the mysql flags, required for your code to compile. On linux, you'd have to include the output of mysql_config --cflags --libs in the make file.
Add those to your makefile and the code should compile just fine.
I understand this has been asked million times but still I just couldn't found the solution.
I am using OSX 10.8, boost 1.50, xcode 4.5.1.
I installed boost using macports.
created an empty xcode project. My main.cpp contains the following code
#include "boost/container/deque.hpp"
int main(int argc, char *argv[])
{
boost::container::deque d(12, 5.5f);
return 0;
}
updated 'header search path' to point to '/opt/local/include'
updated 'library search path' to point to '/opt/local/lib'
tried changing 'c++ language dialect', 'c++ standard library' and other settings with no success at all.
when I build the project, I get error related to semantic issue in allocator_traits.hpp and deque.hpp and I have no idea why. I am afraid as I start using more boost libraries more errors will pop up.
deque.hpp (line 482 and 483)
base specifier must be a class name (ptr_alloc_t and allocator_type)
what else do I need to do to configure boost. why using boost is so complicated?
boost::container::deque is a template class and you must specify which type do you use. In your case this is float:
boost::container::deque<float> d(12, 5.5f);
You can read more about templates here
I am having trouble using the SDL framework in my xcode project, my main (all there is in the project at the moment) currently looks like this:
#include <SDL/SDL.h>
#include <iostream>
int main(int argc, const char * argv[])
{
// insert code here...
std::cout << "Hello, World!\n";
return 0;
}
And the error I am receiving when building is:
Undefined symbols for architecture x86_64:
"_main", referenced from:
start in crt1.10.6.o
(maybe you meant: __Z8SDL_mainiPPKc)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
It does not give me an error about the framework not being found. and I have looked around Stackoverflow for this problem and I did find one person who had their framework in the wrong place on their OS. But I have tried all places (/library/frameworks && /~username~/library/frameworks && /system/library/frameworks) and still no luck.
Additional info:
I did however notice after some searching on the internet that the official website http://www.libsdl.org/download-1.2.php
Does not have a OSX version of the Development library. While many tutorials on how to use SDL on OSX say these are required.
Also I am adding my library via Xcode itself ,not through drag'ndrop. Xcode seems to reckognize it.
Would be much appreciated if anyone could help, going crazy over this error.
UPDATE:
Still no luck, I have followed every step provided by solutions here below. perhaps this screenshot is of any help.
The main() function is corrected, but didn't help. I tried changing the path to the header files, im lost on this one. Does anyone perhaps have any alternatives to building this in xcode?
UPDATE2:
The suggestion worked, however now it is giving me this warning, which won't let me run the application.
Fixed! I removed the path in the build settings. Strange how I still don't know what went wrong, either way. thanks a lot for the help! made my day!
I see three possible problems. The first problem is how you're including SDL.h in your code. You should include SDL.h with the following code:
#include "SDL.h"
The second possible problem is you haven't added the files SDLMain.h and SDLMain.m to your project. Those files are necessary to compile SDL code on Mac OS X. The files are in the devel-lite folder on the SDL disk image.
The third possible problem is that your project doesn't link to the Cocoa framework. The Mac version of SDL uses Cocoa so you need the Cocoa framework in your project.
The following article walks you through the setup of an Xcode 4 project for SDL:
Using SDL with Xcode 4
UPDATE
I noticed a possible problem in how you defined the main() function. You have a space between char and * and another space between * and argv, which could be causing the error. The main() function in my SDL code is defined in the following way:
int main(int argc, char *argv[])