Building Qt5 from source under Cygwin

koahnig

Hi and welcome to devnet

The question I like to raise is: Why are you plan to use Qt under Cygwin after you have installed already Qt for MinGW on windows?

Basically you should be able to compile and link your application under windows as well. Does your application have basic POSIX stuff in there that you would need to have Cygwin as a layer in between?
If this is the case, you want to check whether you can convert stuff that you can use it directly under windows.

It is a while ago (probably almost a decade) that I have used Cygwin. In general, when you are used to linux, it should be at least fairly the same when not exactly the same. I had compiled Qt 4 back then.

If you really have to use Cygwin, I would recommend to start and follow the linux route. When you have problems you need to describe them with the details in posts here. Probably someone will be able to give you enough hints.

Mwvse

Thank you for the thoughtful response, koahnig.

The need for cygwin:
I have seen questions similar to mine in various searches. And, I have seen many answers similar to yours. I understand the reasoning (abstraction/portability) and will certainly consider those factors in future apps. In this particular instance, however, I have this large existing app with a fair amount of unix/linux/posix specific stuff that I simply want to wrap in a GUI.

Progress thus far:
I downloaded the 5.7 Linux tar and found the mkspecs/cygwin-g++/qmake.conf file. I made minor modifications to it and am now able to successfully get through 'configure' within cygwin (I made a few minor mods to a couple of header files to get it to pass (a few preprocessor directives and a few function prototypes)). The 'make' now gets 5 or so minutes in before dying so I am starting to take a look at those. I will come back to this thread with more questions and/or results depending on the circumstances I encounter.

Thanks again!

Mwvse

I have exhausted everything I can think of...build issue with some winsock stuff. Not sure what else I should post to provide additional/helpful diagnostic info. Thanks in advance.

Here are the errors :

make[3]: Entering directory '/home/a/qt-everywhere-opensource-src-5.7.0/qtbase/src/corelib'
g++ -std=c++11 -U__STRICT_ANSI__ -c -pipe -D_REENTRANT -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -O2 -Wall -W -Wvla -Wdate-time -D_REENTRANT -DQT_NO_MTDEV -DQT_NO_LIBUDEV -DQT_NO_EVDEV -DQT_NO_TSLIB -DQT_NO_LIBINPUT -DQT_NO_USING_NAMESPACE -DQT_NO_FOREACH -DQT_HAVE_POLL -DQT_HAVE_PPOLL -DQT_BUILD_CORE_LIB -DQT_BUILDING_QT -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x050000 -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -I. -Iglobal -I../3rdparty/harfbuzz/src -I../3rdparty/md5 -I../3rdparty/md4 -I../3rdparty/sha3 -I../3rdparty/double-conversion/include -I../3rdparty/double-conversion/include/double-conversion -I../3rdparty/forkfd -I../../include -I../../include/QtCore -I../../include/QtCore/5.7.0 -I../../include/QtCore/5.7.0/QtCore -I.moc -I../../mkspecs/cygwin-g++ -o .obj/qglobal.o global/qglobal.cpp

global/qglobal.cpp: In constructor ‘QWindowsSockInit::QWindowsSockInit()’:
global/qglobal.cpp:1944:5: error: ‘WSAData’ was not declared in this scope
     WSAData wsadata;
     ^
global/qglobal.cpp:1947:36: error: ‘wsadata’ was not declared in this scope
     if (WSAStartup(MAKEWORD(2,0), &wsadata) != 0) {
                                    ^
global/qglobal.cpp:1947:43: error: ‘WSAStartup’ was not declared in this scope
     if (WSAStartup(MAKEWORD(2,0), &wsadata) != 0) {
                                           ^
global/qglobal.cpp: In destructor ‘QWindowsSockInit::~QWindowsSockInit()’:
global/qglobal.cpp:1956:16: error: ‘WSACleanup’ was not declared in this scope
     WSACleanup();
                ^
In file included from ../../include/QtCore/qglobalstatic.h:1:0,
                 from global/qglobal.h:1146,
                 from ../../mkspecs/cygwin-g++/qplatformdefs.h:45,
                 from global/qglobal.cpp:41:

koahnig

@Mwvse

Not sure what the issues could be.

Do you have a recent version of gcc compiler in Cygwin?

Other @Moderators may have more detailed knowledge on reasons for your problems. At the moment I would assume that it is compiler version related.

SGaist

Hi,

I'm no Cygwin specialist but why not use the Qt 5 packages provided by them ?

Mwvse

Thanks (again) for the reply. Compiler version below.

I can't find the WSAData type (et al). Perhaps I need a Windows SDK??

$ g++ --version
g++ (GCC) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Mwvse

@SGaist - Thank you very much for the reply.

I did load those packages and did some experimentation but had a number of issues that I haven't yet been able to resolve. Their packages have a mixture of Qt3, Qt4, and Qt5. I loaded all the Qt5 packages I could find but running qmake gave me some so-so results. The generated Makefiles had some weird file/pathnames that didn't make sense to me. I hacked the Makefiles by hand but then had problems getting everything linked. Probably something I am not doing correctly but so far it seems they have a weird mixture of static and dynamic libraries and I can't get an app to resolve all those references/dependencies (I was up til 4:00 am last night trying to get it to work).

I appreciate the suggestion. I will keep working on both options (pre-built cygwin and building my own 5.7 tool chain) and see if I can get one or both figured out. Any other suggestions/comments from the community are greatly appreciated.

koahnig

@Mwvse

@SGaist brings up a good point.

Do you use the newest Cygwin version? This should have at least a Qt 5.5 version with it.

What is your Qt version on linux?

Buckwheat

@Mwvse, Have you tried installing MSYS2? It uses GNU toolchain 6.2.x and installs Qt 5.6.1-2 for both i686 and x86_64 targets. It is a recent fork of Cygwin but does not have all the baggage of Cygwin paths and the layers of DLLs needed. I use this to target development on *nix, Win10, and OSX because of the POSIXness that I do not get with M$VS.

I have found over the last 5 years of using Qt that leaving the building to the Qt folks or the distro builders yields much better results and gives me less headaches in the long run. Why should I spend aggravating hours, days, or even weeks trying to tweak a build when I can get right to the fun stuff!

Mwvse

@koahnig - Thanks for the response. Yes, I have a recent cygwin version and it does have Qt 5.5 (I'm using Qt 5.7 in my Linux environment). Something is still hosed with my Cygwin Qt pre-built/packaged environment. Even a simple qmake project emits a few hiccups in the generated Makefiles. I am still experimenting.

Mwvse

@Buckwheat, I have not looked at MSYS2 but your description and a brief read of their intro sounds like it may be a good option for me. I will pursue this as an option as well. Thank you very much for the insights.