I'm trying to compile a GUI program based on the wxWidgets libraries. I get a lot of undefined references to "something". I tried to add a few libraries manually on the LIBS variable of QMake without success. How can i add all the wxWidgets libraries to QMake without hard coding each library? Below is my .pro file.
# simple.pro
TARGET = sample
HEADERS += main.h simple.h
SOURCES += main.cpp simple.cpp
LIBS += -LC:/SourceCode/Libraries/wxWidgets2.8/lib/gcc_dll/wxmsw28_core_gcc.dll \
-LC:/SourceCode/Libraries/wxWidgets2.8/lib/gcc_dll/wxmsw28_gcc.dll \
-LC:/SourceCode/Libraries/wxWidgets2.8/lib/gcc_dll/wxmsw28_aui_gcc.dll
INCLUDEPATH += C:/SourceCode/Libraries/wxWidgets2.8/include
CONFIG += release
The errors are of the form:
release/simple.o:simple.cpp:(.rdata$_ZTV6Simple[vtable for
Simple]+0x320): undefined reference to
`wxFrameBase::SetStatusBar(wxStatusBar*)'
First, you need to use the .a files to add to the linker.
Then you need to define WXUSINGDLL if you link against the shared libraries.
Additionally, you forgot
wxbase29u.a
Hope that helps.
Related
I tried a simple dylib in macOS and compiled with g++. I made a small sample to test the lib, it works perfect.
Now I made a simple QT app, linked the lib and added the header to the mainwindow.cpp and I always got a fail message Reason: image not found
I read the web and also some other cases here but all is basing on paths.I think it is is not a path problem. Because I made all changes I read in all the cases and also copied the lib in all needed folders, like project folder, build folder. Nothing helps.
I think that QT cannot work with the library and I missed some needed code, like for initialize or export. So that the problem is more inside the dylib and not in QT or Paths values.
Maybe someone can help me here out?
I have tried:
INCLUDEPATH += $$PWD/mylib
DEPENDPATH += $$PWD/mylib
macx: LIBS += -L$$PWD/mylib/ -lmylib
I tried to copy the lib to the build folder and also to the executable folder.
Also edited:
/Users/ingoforster/Documents/Development/Playground/TestGround/mylib:/Users/ingoforster/Qt/5.9.1/clang_64/lib
in Project settings DYLD_LIBRARY_PATH
Set also to DYLD_FRAMEWORK_PATH
Cpp
#include "mylib.hpp"
char *mMessage(void) {
return "Ein sonniger Tag";
}
header
#include <stdio.h>
#include <iostream>
using namespace std;
char *mMessage(void);
compiled with
g++ -std=c++0x --verbose -dynamiclib -o libmylib.dylib mylib.cpp
Sample
#include "mylib.hpp"
int main(void){
char* Ingo = mMessage();
std::cout << mMessage();
}
compiled with
g++ -std=c++0x test.cpp -L./ -lmylib
Actual result is that the sample runs perfect.
But in QT I got:
dyld: Library not loaded: libmylib.dylib
Referenced from: /Users/ingoforster/Documents/Development/Playground/build-TestGround-Desktop_Qt_5_9_1_clang_64bit-Debug/TestGround.app/Contents/MacOS/TestGround
Reason: image not found
10:09:05: The program has unexpectedly finished.
10:09:05: The process was ended forcefully.
/Users/ingoforster/Documents/Development/Playground/build-TestGround-Desktop_Qt_5_9_1_clang_64bit-Debug/TestGround.app/Contents/MacOS/TestGround appears to be compile-linked to your library code but perhaps has not been formally installed to the executable. macdeployqt usually deals with this issue.
You may also do this manually with otool and install_name_tool:
otool -L /path/to/executable
This will list the installed paths to the dylibs in use. You will see your dylib, that is the "/old/path/to/libmylib.dylib"
install_name_tool -change /old/path/to/libmylib.dylib /new/path/to/libmylib.dylib /path/to/executable
Usually, in an .app, the dylib is installed to a subdirectory within the .app folder.
Application.app/
Contents/
MacOS/
executable
Frameworks/
libmylib.dylib
With install_name_tool you can point to the dylib relative to the executable path to make the app portable.
install_name_tool -change /old/path/to/libmylib.dylib #executable_path/../Frameworks/libmylib.dylib /path/to/executable
After some hard investigation and running into the wrong direction with the given answers here I found out, that QTCreator will do all its own:
QTCreator Pro file have to contain:
macx: LIBS += -L$$PWD/mylib/ -lmylib
INCLUDEPATH += $$PWD/mylib
DEPENDPATH += $$PWD/mylib
MediaFiles.files += mylib/libmylib.dylib
MediaFiles.path = Contents/MacOS
QMAKE_BUNDLE_DATA += MediaFiles
I am trying to run a QT project on Windows that I have developed on Linux Ubuntu. Unfortunately, I cannot manage it to properly link the boost library. Here is a detailed description of the problem.
I downloaded MinGW from https://nuwen.net/mingw.html, version 13.5, such that the gcc version 5.3.0 matches the MinGW version of QT. The reason to choose this version of MinGW is that it contains the boost libraries for compression such as zlib. From the command line I compile and run my program without any problems:
g++ -std=c++11 -w -IC:/MinGW/include -LC:/MinGW/lib bAya.cpp A.o B.o C.o -o baya -lboost_iostreams -lz -lbz2
where A,B, C are my pre-compiled object files.
In QT creator I selected the MinGW compiler (C:\MinGW_53\MinGW\bin\g++.exe) and created a new default kit with the compiler.
My .pro file looks as follows:
MAKE_CXXFLAGS += -std=c++11
INCLUDEPATH += C:/MinGW_53/MinGW/include \
C:/Users/kuzk/Documents/src
LIBS += -LC:/MinGW_53/MinGW/lib/mylib \
-lboost_system \
-lboost_iostreams \
-lz \
-lbz2
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
SOURCES += main.cpp\
mainwindow.cpp \
../src/A.cpp \
../src/B.cpp \
../src/C.cpp
HEADERS += mainwindow.h \
../src/A.h \
../src/B.h \
../src/C.h
The folder C:/MinGW_53/MinGW/lib/mylib contains my .a files such as libboost_iostreams.a
When I build it, I get many undefined reference errors such as
error: undefined reference to `boost::iostreams::zlib::default_strategy'
Interestingly, if C:/MinGW_53/MinGW/lib/mylib contains also libstdc++.a I also get linking errors to std::cout, std::ifstream etc.
I am currently stuck and I will be very helpful for any feedback.
Best,
Konstantin
Adding the library path for boost_iostreams:
-LC:/MinGW/lib \
after the line:
LIBS += -LC:/MinGW_53/MinGW/lib/mylib \
should fix it.
At the end I was able to resolve the problem. Here is what I did. I am using QT 5.7 on Windows 10.
I compiled boost using QT's console as described here: http://cpp-qt-mac-win.blogspot.co.uk/2011/10/qt-boost-for-beginners-step-by-step.html
Then I created a new project and added the paths to boost and the necessary libraries, as described in my question.
An important note. I tried to update the paths in the existing project, by running qmake and then rebuilding the project. I was getting the very same errors as I was getting with the old paths to "standard" boost. Apparently, something was cached and the changes didn't do anything. However, if I give a wrong path to a library it complained. So, QT has very confusing behavior. If someone can explain it, it will be helpful.
I just installed RtMidi for a project and compiled it. The examples in the tests folder work and so does my code if I put it in the folder and include it in the Makefile that compiles all the examples. How can I use RtMidi in a project with #include <RtMidi.h> instead of having my code in the tests folder? More specifically, what should I put in my Makefile? I've read a bit about dynamic and static libraries but I have no idea what I should be looking for. I've tried adding -llibrtmidi and /usr/local/lib/librtmidi.a without success.
In a standard Makefile, the CXXFLAGS macro defines flags for the C++ compiler. You will need to add -I<path to header directory> to this macro for the compiler to find the RtMidi header files.
Then you will need to add -L<path to lib directory> to the link step of the Makefile so that -lrtmidi will find the library file. (Note that you omit the lib prefix for the -l command)
Based on your description of your environment, you may require something like
CPPFLAGS += -I/usr/local/include
LDFLAGS += -L/usr/local/lib
LDLIBS += -lrtmidi
in your Makefile. make uses a lot of these implicit variables.
I'm trying to use the Sha512 function in openSSL but can't seem to get it to work as I get compiler errors just starting into the code. I include #include <openssl/sha.h> at the top of the .cpp file, then in the action of a button event I put just the following code below.
SHA512_CTX ctx;
SHA512_Init(&ctx);
//Will uncomment below in later if I get SHA512_Init to work
//SHA512_Update(&ctx, string, strlen(string));
//SHA512_Final(digest, &ctx);
I get a linker error telling my undefined symbols for architecture x86_64, implying the function does not exist?
I'm aware QT 5 has a hash function, but I'm limited to QT 4.8 so I can not use the cryptographic sha512 hash function available in the QT 5+ framework.
Any help is appreciated!
Used macports to install openssl
I'm using Mac OS 10.9.2
MAKE FILE
#-------------------------------------------------
#
# Project created by QtCreator 2014-06-11T20:27:49
#
#-------------------------------------------------
QT += core gui network
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = ExchangeTab
TEMPLATE = app
LIBS += -L/usr/include/openssl -openssl
INCLUDEPATH += /usr/include/openssl
SOURCES += main.cpp\
mainwindow.cpp \
httpsocket.cpp \
cloaksend.cpp \
exchange.cpp
HEADERS += mainwindow.h \
httpsocket.h \
cloaksend.h \
exchange.h
FORMS += mainwindow.ui
RESOURCES += \
AppResources.qrc
Looking for cross platform solution please.
You need to link to the right library (openSSL)
Have a look here: How to Include OpenSSL in a Qt project
Specifically, add this to your .pro file.:
LIBS += -L/opt/local/lib/ -lcrypto
For including .h files add this line to your .pro file :
INCLUDEPATH += /opt/local/include
[1] says that the default include path will be /opt/local/include/.
LIBS += -L/usr/include/openssl -openssl
INCLUDEPATH += /usr/include/openssl
This looks incorrect. The OpenSSL libraries are libcrypto (-lcrypto) and libssl (-lssl). There is nolibopenssl(-lopenssl). Try:
LIBS += -L/usr/lib -lcrypto
INCLUDEPATH += /usr/include/openssl
But the libraries are version 0.9.8. You might consider upgrading to 1.0.1h.
$ ls /usr/lib | grep crypto
libcrypto.0.9.7.dylib
libcrypto.0.9.8.dylib
libcrypto.dylib
libk5crypto.dylib
And
$ /usr/bin/openssl version
OpenSSL 0.9.8y 5 Feb 2013
If you choose to upgrade, OpenSSL will install into /usr/local/ssl. Avoid mixing/matching version of OpenSSL with the following.
INCLUDEPATH += /usr/local/ssl/include/openssl
LIBS += /usr/local/ssl/lib/libcrypto.a
Its OK to specify objects and archives in LIBS. See How to add object files to a project in Qt.
Okay so I may have answered my own question but I will need some help understanding why it worked.
My make file was indeed the problem. I added the following 3 lines.
INCLUDEPATH += $$OPENSSL_INCLUDE_PATH
LIBS += $$join(OPENSSL_LIB_PATH,,-L,)
LIBS += -lcrypto
Then it magically compiled just fine. I found these in another project made with QT that compiled for OpenSSL.
Interestingly enough. I removed the top two lines so only the following remained. Then ran the clean on my project to be sure the code was being recompiled.
LIBS += -lcrypto
This also just 'worked' without linker errors. It looks like that is the only command I need. Question is... will that be cross platform friendly if I take this code and compile on linux or windows? That I am not sure, but this worked.
Resolved. When I add my library as a normal internal library everything is fine. What I had failed to do was use the MY_LIBRARY_EXPORT macro on some free functions defined in a namespace. Somehow I had manipulated the library import in such a way to get those functions working, but it broke in other ways as described here.
I have not been able to use a shared library using the Qt Creator wizard. I have tried with dynamic linkage, and have failed, and cannot use as a static lib either. In both cases I get an 'undefined reference to `IMP_*' error.
Here are my pro files. They are both in the same SUB_DIR parent project and the paths are correct.
Relevant parts of the library pro file:
TARGET = Prospec
TEMPLATE = lib
CONFIG += staticlib
QMAKE_CXXFLAGS += -std=c++11
DEFINES += PROSPEC_LIBRARY
The entirety of the user .pro file. (ProspecTest is a unit test project for Prospec).
#-------------------------------------------------
#
# Project created by QtCreator 2013-12-12T15:04:30
#
#-------------------------------------------------
QT += testlib
QT -= gui
TARGET = prospectest
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
QMAKE_CXXFLAGS += -std=c++11
SOURCES += prospectest.cpp \
mltest.cpp \
convertertest.cpp \
numericitemtest.cpp
DEFINES += SRCDIR=\\\"$$PWD/\\\"
HEADERS += \
utilities.h \
mltest.h \
convertertest.h \
numericitemtest.h
win32:CONFIG(release, debug|release): LIBS += -L$$PWD/../Prospec/release/ -lProspec
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/../Prospec/debug/ -lProspec
INCLUDEPATH += $$PWD/../Prospec/debug
DEPENDPATH += $$PWD/../Prospec/debug
win32:CONFIG(release, debug|release): PRE_TARGETDEPS += $$PWD/../Prospec/release/libProspec.a
else:win32:CONFIG(debug, debug|release): PRE_TARGETDEPS += $$PWD/../Prospec/debug/libProspec.a
# Boost
INCLUDEPATH += C:/boost/boost_1_55_0/
LIBS += "-LC:/boost/boost_1_55_0/stage/lib/"
EDIT: the undefined reference errors happen only where I invoke functionality in a source file. For instance, if I construct a library object I get the error, but if I move that objects constructor into a header file, then compile is OK. Right now I'm not sure if the problem is due to the Qt environment, or me not understanding shared libraries in general.
The error you describe points to a linker error. It happens when a necessary object/lib file is not specified. The most likely scenario is this: you include a header and use a function from that header, but don't specify in which library that function is defined.
Small example:
//test.c
#include <winsock.h>
int main() { gethostbyname("localhost"); }
'undefined reference' linker error:
>gcc test.c
cczICEqq.o:test.c:(.text+0x1e): undefined refer ence to `gethostbyname#4'
collect2.exe: error: ld returned 1 exit status
In this case you would have to specify libwsock32.a like this:
gcc test.c -lwsock32
Also, note that a libsomething.a is not the only place where a reference can be resolved. You might have missed an object file.
Unfortunately without more details I am not able to tell you the exact problem.
You probably forgot to export your symbols, as described here on MSDN and in various questions on this website. It's a pain in general, and there are a few ways to handle this, none much better than the other.
This makes it so that the DLL and import library actually contain a reference to the symbols you compiled into it. You can compare it partially to GCC's symbol visibility, although that only works in Linux, and GCC also supports the stuff described on MSDN for Windows.
Had the same problem just now. Build was working fine on macOS/OSX but not on Windows with the same codebase. Thanks to rubenvb, who pointed me in the right direction. Here the full solution, how to do it for Qt:
Use Q_DECL_EXPORT on functions when building the lib. And use Q_DECL_IMPORT when using the functions from the lib.
Example how to do this here: https://wiki.qt.io/How_to_create_a_library_with_Qt_and_use_it_in_an_application#Creating_a_shared_library
Solved the problem in my case, hope it helps!