Qt seems to load openssl dynamically at runtime, as seen in this question.
And apparently, it gets the system openssl. For instance, on macOS, I would rather use the homebrew-installed openssl, and package it into my dmg, so that the users don't need to install it themselves.
How can I tell Qt where to look for the libraries it links? Is there something to do with the qt.conf file?
you can do something like that in your .pro file:
win32-msvc* {
LIBS += -LC:/openssl/lib/ -llibeay32
LIBS += -LC:/openssl/lib/ -lssleay32
INCLUDEPATH += C:/openssl/include
}
left click on your project -> add library -> external library -> choose the .lib file and the include folder for the library. check for which platform it is.
It will put the specific platform dependend commands to your project .pro filefile.
Related
I am trying to run a program in Qt5.6 with openCV3.1, but no matter what I do, it does not detect openCV include.
Projects -> Build Environment -> Include :
I added C:\opencv\opencv3.1.0\opencv\build\include
Projects -> Build Environment -> LIB:
I added C:\opencv\opencv3.1.0\opencv\build\x64\vc14\lib
However, still in the code there is a yellow line indicating that it doesn't detect opencv:
and there are lots of errors like this:
The environment variable for openCV is also set as:
C:\opencv\opencv3.1.0\opencv\build
How should I install Qt with openCV to avoid these problems?
In the .pro file, add the following lines:
INCLUDEPATH += C:\opencv\opencv3.1.0\opencv\build\include
LIBS += -LC:\opencv\opencv3.1.0\opencv\build\x64\vc14\lib \
opencv310.lib \
And also you need to add the .dll file's path C:\opencv\opencv3.1.0\opencv\build\x64\vc14\bin to the system path (this time you need to restart the Qt IDE)
I compiled a library using the MinGW toolchain provided with Qt 5.0.2 on Windows. As a result I received a library.so file. First I failed using the library in a Qt application, but now I found out that everything works fine when I make a copy of the liblibrary.so file and call it liblibrary.dll or liblibrary.lib (which is the only file ending supported by the add library wizard in QtCreator).
Now I wonder if this is normal or if I should change something in order not to have both files (which are exact copies). Leaving one away makes the application crash during start up. I added the library as follows to my Qt pro file:
LIBS += -L"../path/to/library" -llibrary
INCLUDEPATH += $$quote(../path/to/library)
EDIT: I compiled the library using the MinGW of Qt, not as Qt project but using mingw32-make and the provided Makefile. As a result I get the liblibrary.so.
EDIT: It seems to work also when renaming the copy to liblibrary.dll instead of .lib. But still, I need two files to make the application work -- the .so and the .dll.
Chris
That's weird, I think you should get a *.a and *.dll files when building a shared lib with MinGW on Windows, as said in the documentation:
In windows, MinGW will output .a and .dll, MSVC2010 will ouput .lib and .dll. In linux, MinGW will output .so, .so.1, .so.1.0 and .so.1.0.0 – .lib, .a and .so are import libraries.
You definitely shouldn't rename your file!
Be careful to:
not to include the "lib" prefix after "-l" in your project file.
put everything after after "-l" in lower case as you're on Windows
not adding any extension to your library name after "-l"
add and reference the .h file used in your library
A real example using QtWebsocket lib:
INCLUDEPATH += "$${PWD}/include/"
LIBS += -L"$${PWD}/libs/" -lqtwebsocket
...
HEADERS += ... \
$${PWD}/include/QWsSocket.h \
...
In my include/ folder, I have the following file:
QWsSocket.h (taken from original project - required)
In my libs/ folder, I have the following file:
libQtWebsocket.a
QtWebsocket.dll
Edit: I struggled with this too initially. Have you tried to build your lib as a static lib instead (CONFIG += staticlib in your library project)? This might help you getting you *.pro file right before switching to using the shared library.
Edit 2: Ok, the fact that you get a *.so file is still a bit odd. In this question
the user has the same issue as you and keep both files, which is just a workaround. According to a later answer it seems that you need to modify your makefile to generate a file with the proper extension. Maybe this will help: http://www.mingw.org/wiki/sampleDLL
I'm new to Qt, I've done some Googleing and can't find a detailed enough answer.
I need to use OpenSSL in my qmake-based Qt project. How do I go about downloading/installing/linking it so I can just do an include statement and use its functions in my code?
Assuming Windows, you can download its installation from Win32 OpenSSL Installation Project page. You can choose one for 64-bit windows developing or for 32-bit. Just run the setup and everything will be done easily. The default installation directory is : C:\OpenSSL-Win32
In Qt creator, if you then want to link a library to your project you can just add this line to your .pro file(project file ) :
LIBS += -L/path/to -llibname
So here's what we do for this library( for example to link ubsec.lib )
LIBS += -LC:/OpenSSL-Win32/lib -lubsec
Pay attention to -L and -l.See this question. You don't even need to specify .lib at the end of the library name.
For including .h files add this line to your .pro file :
INCLUDEPATH += C:/OpenSSL-Win32/include
after that you can include a file like this :
#include <openssl/aes.h>
From George at Unable to use AES files of OpenSSL in Qt Creator:
If this is on Linux, add the following into your .pro file:
PKGCONFIG += openssl
It will handle all necessary header paths, compile-linker options and
the libraries.
And make sure you have the openssl-devel package installed in your
system.
I was working on Win 7 (32) with Qt5.5, and non of these answers worked for me.
So I just want to share a solution that finally worked:
1. I have OpenSSL installed in C:\OpenSSL-Win32
2. In c:\OpenSSL-Win32\MinGW there are two library files:
libeay32.a & ssleay32.a
3. I've made a copy of each of them an renamed the extensions:
libeay32.a -> libeay32.lib & ssleay32.a -> ssleay32.lib
4. I linked libraries in my .pro file this way:
LIBS += -LC:/OpenSSL-Win32/lib/MinGW -llibeay32
LIBS += -LC:/OpenSSL-Win32/lib/MinGW -lssleay32
INCLUDEPATH += C:/OpenSSL-Win32/include
5. I copied 3 .dll files from C:\OpenSSL-Win32:
(libeay32.dll, libssl32.dll, ssleay32.dll)
to my build/debug folder:
(build-XXXXX-Desktop_Qt_5_5_1_MSVC2012_32bit-Debug/debug)
I hope this will help.
If you use cmake as build system for your project, then you may include FindOpenSSL.cmake as follows:
#set(OPENSSL_USE_STATIC_LIBS TRUE) # if you want to use static libssl.a and libcrypto.a
include(FindOpenSSL)
#add_executable(${PROJECT_NAME} ...) or add_library(${PROJECT_NAME} ...)
target_link_libraries(${PROJECT_NAME} PRIVATE ${CMAKE_DL_LIBS} OpenSSL::SSL OpenSSL::Crypto)
${CMAKE_DL_LIBS} is required on Linux systems to avoid link-time errors like "dlopen symbol not found...". On windows it became empty.
If openssl installation directory is not being standard, then you should provide OPENSSL_ROOT_DIR to cmake, e.g. to add set(OPENSSL_ROOT_DIR "C:/msys64/mingw32") before include or to specify -DOPENSSL_ROOT_DIR:PATH=C:/msys64/mingw32 to cmake executable (in "Projects"->"Build settings"->"CMake" tab).
if you are on win7,and your qt version is mingw, and u install openssl from http://slproweb.com/products/Win32OpenSSL.html ,make sure your lib should be in the OpenSSL-Win32/lib/MinGW, and add a "lib" pre to the libeay32.a and ssleay32.a 。
I made a custom library and i compiled it into a dll (qustom.dll).
Now i want to compile another project using this dll.
What i did is to import the header files in the project and add this line in my .pro file
LIBS += -lqustom
but i get "error: cannot find -lqustom"
also i tried
LIBS += qustom.dll
and
LIBS += -libqustom.a
qustom.dll is in the project directory
Also i tried
OTHER_FILES += \
qextserialport1.dll
but didn't work either
Am i missing something here?
Missing a path perhaps? -L/path/to/dlls -ldllname
Qt plays nicely with CMake. I use that and I never get dependency/path headaches like this any more.
I want to use CTelephony API in Qt Symbian project but after including etel3rdparty.h and etel3rdparty.lib as library and header in .pro file like this:
LIBS += C:/NokiaQtSDK/Symbian/SDK/epoc32/release/armv5/lib/etel3rdparty.lib
INCLUDEPATH += C:/NokiaQtSDK/Symbian/SDK/epoc32/include
I am getting a lot of compilation errors.
Please share if someone faced and find the solution of this problem.
You are not supposed to include each library with the complete path in the .pro file. You need only the name of the lib, without the extension, prefixed with -l, i.e. in your case
LIBS += -letel3rdparty
Also, you would normally not need to add epoc32\include to the include path, as it's added by default.