Boost: use it with Qt

[Handi]

I cannot express how much time I've wasted over the last few weeks trying to get shit work with boost.

Anyway, I'm trying to setup boost with Qt Creator right now, and I'm having linking issues.

I've built my boost libraries for MinGW using:

b2 --build-dir=build toolset=gcc --build-type=complete stagegcc

b2 --build-dir=build toolset=gcc --build-type=complete stagegcc

To copy to clipboard, switch view to plain text mode 

Now, I've added the following lines to my .pro:

LIBS += -L"c:/boost_1_47_0/stagegcc/lib/"
INCLUDEPATH += c:/boost_1_47_0/
DEPENDPATH += c:/boost_1_47_0/

LIBS += -L"c:/boost_1_47_0/stagegcc/lib/"
INCLUDEPATH += c:/boost_1_47_0/
DEPENDPATH += c:/boost_1_47_0/

To copy to clipboard, switch view to plain text mode 

I'm using boost's ASIO library, which needs boost::system library
when I try to compile my project I get the error:

undefined reference to 'boost::system::generic_category()'

undefined reference to 'boost::system::generic_category()'

To copy to clipboard, switch view to plain text mode 

I've read several threads about how to get boost to work with Qt, but none of them helped so far.
Also, I'm relatively new with Qt, last time I used it was 2 years ago for one project, so please be detailed in your instructions.

I HATE boost right now.
No success at all configuring it with Code::Blocks
Managed to make it work with MSVC just to discover that it doesn't work with c++/cli so I cannot make any GUIs.

Thank you

[jainishjain]

I too faced same problem couple of years ago while working on application using Qt and boost together.

I worked by defining QT_NO_KEYWORDS macro (this will prohibit using Qt's signals and slots keywords which clashes with Boost) and then used Q_SIGNALS, Q_SLOT instead of Qt's signals and slots keywords while declaring in header file. You
http://www.boost.org/doc/libs/1_49_0...gnals/s04.html

Hope that helps.

Jainish

[wysota]

You are not linking against boost, you just told your compiler where to look for it but you didn't tell it to actually look for it. Add a LIBS += -l<libname> entry to your project file. By the way... What Boost ASIO does, Qt already does. So maybe it's easier to just port your code to Qt to get rid of the additional dependency.

[Handi]

Thanks for the replies,

I've added:
LIBS += -lboost_system-mgw46-mt-1_47\
-lboost_thread-mgw46-mt-1_47

and
#define BOOST_THREAD_USE_LIB
to my source file

Now I simply get "collect2: ld returned 1 exit status", no details...
This is bad

I'm slowly considering the option of dropping boost altogether now...

[wysota]

You surely get more than this obscure message.

[Handi]

I wish I did...

But no, there's only 1 line and it is what I wrote. I've seen that before with gcc/g++.

Perhaps I'm not linking the right libraries or I forgot to do some cryptic define?
I'm really not sure which particular libraries I should be linking... every library has different versions, and while I checked the help about what they mean, I am still unsure. In any case I tried different variations and it is always the same message. If I omit to include one of those libraries I get the usual "undefined reference to xxxx" message.

---

Added after 44 minutes:

Well, I switched to the compile tab, it did effectively write more info there

"undefined reference to `WSAStartup@8'

"undefined reference to `WSAStartup@8'

To copy to clipboard, switch view to plain text mode 

I googled that and the fix was to add a winsocket library, "-lws2_32".
Now everything compiles fine, but I get a runtime error "0xc0000139", which I again googled and it means "DLL not found"
Now I don't yet know which DLL is it complaining about. I assume it is a boost related one, since QT didn't give any troubles before I added the boost related source file.

At least there seems to be some progress...

EDIT:
Well, I tried to exec the generated .exe file directly from windows explorer, and it says QtCored4.dll is missing.
It seems like it does this for any qt generated program when I try to execute it directly by double-clicking the exe file, even if the program runs fine when executed through the IDE.
This makes it hard to find which dll my boost program is complaining about.

[Ginsengelf]

[I]
Well, I tried to exec the generated .exe file directly from windows explorer, and it says QtCored4.dll is missing.
It seems like it does this for any qt generated program when I try to execute it directly by double-clicking the exe file, even if the program runs fine when executed through the IDE.

Hi, this is probably because the QtCored4.dll is not in the standard search path for libraries. Windows looks for DLLs in some standard system directories and also in the directory where the exe is placed. You could resolve your error by copying the QtCored4.dll to the directory with the exe.

Ginsengelf

[Handi]

Seems like it creates all sorts of problems when I copy-paste Qcored4.dll in the folder. It then asks for 2 other dlls. When I copy those in the build folder, I get some weird error such as "The procedure entry point _Z11qt_assert_xPKcS0_S0_i could not be located in the dynamic link library QtCored4.dll". And that's for an application that actually WORKS in Qt... so I didn't even dare trying that with my boost program.

Anyway, I gave up on boost. I ended up using QextSerialPort, it seems like it works well with the SPP service through bluetooth.
I think I've spent more time trying to get boost to work with different IDEs than actual work.

[wysota]

This is kind of basic Windows programming knowledge. All required DLLs need to be available for the system linker to find them. You can do that by placing them in the same directory as the executable or putting them into %PATH%. The DLLs you need are the ones the application has been built against and I'm not talking about the file names but the files themselves. So you can't copy an arbitrary QtCored4.dll, you have to copy the one your compiler used. The same goes for any other library used by your application.

[Handi]

Thanks, I appreciate the help wysota.

Unfortunately I do not have the privilege of having basic windows programming knowledge.
I am not a software engineer, and all my programming knowledge is mostly language depended, not so much info about given environments.

Anyway, I added my qt/bin directory and boost libs directory to the path, now it looks like everything compiles and executes!
The only problem is that my boost program executes only when I double click the exe from windows explorer, and still returns the dll not found when ran from QtCreator.
Did I forget to add something in my .pro file?

This is what I added to path:

C:\Qt\2010.04\qt\bin;C:\boost_1_47_0\stagegcc\lib

C:\Qt\2010.04\qt\bin;C:\boost_1_47_0\stagegcc\lib

To copy to clipboard, switch view to plain text mode 

This is my .pro file:

QT       += core gui
 
TARGET = imugui1
TEMPLATE = app
 
SOURCES += main.cpp\
        mainwindow.cpp \
    btserial.cpp
 
HEADERS  += mainwindow.h \
    btserial.h
 
FORMS    += mainwindow.ui
 
LIBS += -L"c:/boost_1_47_0/stagegcc/lib/"
LIBS += -lboost_system-mgw46-mt-1_47 \
	-lboost_thread-mgw46-mt-1_47 \
	-lws2_32
 
INCLUDEPATH += c:/boost_1_47_0/
DEPENDPATH += c:/boost_1_47_0/

QT       += core gui

TARGET = imugui1
TEMPLATE = app

SOURCES += main.cpp\
        mainwindow.cpp \
    btserial.cpp

HEADERS  += mainwindow.h \
    btserial.h

FORMS    += mainwindow.ui

LIBS += -L"c:/boost_1_47_0/stagegcc/lib/"
LIBS += -lboost_system-mgw46-mt-1_47 \
	-lboost_thread-mgw46-mt-1_47 \
	-lws2_32

INCLUDEPATH += c:/boost_1_47_0/
DEPENDPATH += c:/boost_1_47_0/

To copy to clipboard, switch view to plain text mode 

[wysota]

Did I forget to add something in my .pro file?

The .pro file has nothing to do with it. Its role ends when the program is compiled. What you are having problems with is executing the program. You need to make sure the required libraries can be found by the system linker when the application is ran. I'd suggest copying boost libraries to C:\Windows\system32 (or \system), then the linker should always find them.

[Handi]

Hmm that sounds like a weird workaround. Isn't there a better way to tell the linker where to look for libs?

[wysota]

Hmm that sounds like a weird workaround. Isn't there a better way to tell the linker where to look for libs?

It is a weird workaround, however if you don't feel comfortable with the system, that's what I'd suggest. A better way is to make sure the linker can find the needed DLL by putting it in the same directory as the executable of the application or by adding the directory containing the DLL to system %PATH% (which is, from what you have said, what you have already tried, alas without success).