Linux: build Qt WebKit against a specific version of ICU?

agarny

Hi,

I currently use Qt 5.6.1 LTS for my project and because it requires Qt WebKit, I build Qt WebKit myself. This is all working fine on Windows and OS X, but I am having a small problem on Linux.

Basically, I am building Qt WebKit on Ubuntu 14.04 LTS and if I check against which version of ICU it is built, I get the following:

$ ldd libQt5WebKit.so.5.6.1 | grep libicu
	libicui18n.so.52 => /usr/lib/x86_64-linux-gnu/libicui18n.so.52 (0x00007fc3e8ba3000)
	libicuuc.so.52 => /usr/lib/x86_64-linux-gnu/libicuuc.so.52 (0x00007fc3e882a000)
	libicudata.so.52 => /usr/lib/x86_64-linux-gnu/libicudata.so.52 (0x00007fc3e3842000)

So, also it's not building against Qt's version of ICU, it means that if I deploy my application on Ubuntu 14.04 LTS, then it's still working fine, but not if I deploy it on Ubuntu 16.04 LTS since it cannot find libicui18n.so.52 & Co.

So, my idea is obviously to build Qt WebKit against Qt's version of ICU, not least because it's also the version used by the other Qt libraries that are shipped along with m y application, but... how can I do that? (Sorry, I normally use CMake, so I am not at all familiar with .pro/.pri/etc. files.)

Cheers, Alan.

agarny

Someone just told me that I could try to deploy both Ubuntu 14.04 LTS's version of ICU, as well as Qt's version of ICU. Well, I have just given it a try and indeed it's working fine. I am therefore going to go with this 'solution', although I would still like to do what I described above.

Konstantin Tokarev

It should be quite painful to distribute 2 copies of ICU because you need to distribute 2 copies of data bundles as well. Unfortunately Qt SDK does not provide any way to build against its copy of ICU, but still there is a workaround

Install (from sources or some binary packages, does not matter) the same ICU version as used in SDK. For example, if in SDK you see libicuuc.so.56.1, you should get ICU 56.1
Build QtWebKit against this ICU installation. By default QtWebKit uses pkg-config to find ICU, so you can override system ICU with your newly installed ICU by pointing PKG_CONFIG_PATH variable to location of icu-i18n.pc from your ICU installation (e.g. $prefix/lib/pkg-config)

agarny

Thanks Konstantin, I will give your suggestion a try when I get a chance. (I agree, it's not 'neat' to ship two different copies of ICU, but at least it works for now.)

agarny

@Konstantin-Tokarev, I have just given your suggestion a try, but I am clearly missing something. Indeed, here is what I did (keeping in mind that I am using Qt 5.6.1 LTS):

I retrieved ICU 56.1's source code from http://site.icu-project.org/download and built it as follows:

$ cd [ICU]
$ mkdir build
$ cd build
$ ../source/runConfigureICU Linux --prefix=[ICU]/install
$ make
$ make install

From there, I retrieved Qt WebKit's source code from http://download.qt.io/community_releases/5.6/5.6.1 and built it as follows:
- ```
$ cd [QtWebKit]
$ PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig qmake
$ make
```

At this stage, I thought my copy of Qt WebKit would refer to ICU 56.1, but if I check Qt WebKit's dependencies, I can see that it's still referring my system's ICU (!!):

$ ldd [QtWebKit]/lib/libQt5WebKit.so.5.6.1 | grep libicu
        libicui18n.so.52 => /usr/lib/x86_64-linux-gnu/libicui18n.so.52 (0x00007fba553e7000)
        libicuuc.so.52 => /usr/lib/x86_64-linux-gnu/libicuuc.so.52 (0x00007fba5506e000)
        libicudata.so.52 => /usr/lib/x86_64-linux-gnu/libicudata.so.52 (0x00007fba50077000)

Clearly, I am missing something, but what is it?...

agarny

Ok, I have got it to work (yeah!). Basically, rather than building Qt WebKit using:

$ cd [QtWebKit]
$ PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig qmake
$ make

I had to build it using:

$ cd [QtWebKit]
$ export PATH=[ICU]/install/bin:$PATH
$ export LD_LIBRARY_PATH=[ICU]/install/lib:$LD_LIBRARY_PATH
$ export PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig:$PKG_CONFIG_PATH
$ qmake
$ make

I would have thought that setting PKG_CONFIG_PATH would have been enough, but clearly not!

Konstantin Tokarev

Looks like it's deficiency of ICU *.pc files, which don't provide appropriate -L flags with library path when non-default prefix is used

agarny

Actually, my bad, we don't need to export a new PATH and LD_LIBRARY_PATH in addition to exporting a new PKG_CONFIG_PATH. In the end, we only need to export a new PKG_CONFIG_PATH.

However, it would seem that not only qmake needs to know about PKG_CONFIG_PATH, but also make (??), hence exporting PKG_CONFIG_PATH rather than setting it as I originally did using:

$ PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig qmake

In conclusion, I am now able to build QtWebKit by simply using:

$ cd [QtWebKit]
$ export PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig:$PKG_CONFIG_PATH
$ qmake
$ make

Konstantin Tokarev

@agarny No, I don't see any calls to pkg-config in generated Makefiles, so PKG_CONFIG_PATH should not have an effect on make

agarny

@Konstantin-Tokarev, I appreciate what you are saying, hence my "??" in relation to make above.

Still, and just to be 100% sure, I have just rebuilt Qt WebKit using:

$ cd [QtWebKit]
$ PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig qmake
$ make

and sure enough, the resulting libraries don't work (they refer to the system version of ICU, i.e. version 52.1) while everything works fine (i.e. the libraries refer to version 56.1 of ICU) when building Qt WebKit using:

$ cd [QtWebKit]
$ export PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig:$PKG_CONFIG_PATH
$ qmake
$ make

Anyway, the latter works fine and, at this stage, this is what matters to me, evenb though I don't understand why I need to export a new PKG_CONFIG_PATH rather than modify it 'inline'...

Konstantin Tokarev

@agarny Ah, unless you run qmake with "-r" option it is recursively called in subdirs in make time

agarny

Well, I have just given it a try, i.e.

$ cd [QtWebKit]
$ PKG_CONFIG_PATH=[ICU]/install/lib/pkgconfig qmake -r
$ make

First, I got the following at the end of the call to qmake:

Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WTF/WTF.pro
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/JavaScriptCore/JavaScriptCore.pro
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/ThirdParty/ANGLE/ANGLE.pro
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/ThirdParty/leveldb/leveldb.pro
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/ThirdParty/leveldb/Target.pri
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebCore/WebCore.pro
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit/WebKit1.pro
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit2/WebKit2.pro
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/QtWebKit.pro
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/api.pri
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/widgetsapi.pri
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit2/WebProcess.pro
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit2/PluginProcess.pro
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit/qt/declarative/declarative.pro
  Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit/qt/declarative/public.pri
  Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit/qt/declarative/experimental/experimental.pri
 Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit/qt/examples/examples.pro
  Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WebKit/qt/examples/platformplugin/platformplugin.pro
WARNING: DESTDIR: Cannot access directory '/opt/Qt/5.6/gcc_64/plugins/webkit'
Reading /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Tools/Tools.pro

Then, when building Qt WebKit, I eventually got:

/usr/bin/ld: warning: libicui18n.so.56, needed by /opt/Qt/5.6/gcc_64/lib/libQt5Core.so, may conflict with libicui18n.so.52
/usr/bin/ld: /home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/WTF//.obj/wtf/unicode/icu/CollatorICU.o: undefined reference to symbol 'ucol_setAttribute_56'
/opt/Qt/5.6/gcc_64/lib/libicui18n.so.56: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make[2]: *** [../../bin/jsc] Error 1
make[2]: Leaving directory `/home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/JavaScriptCore'
make[1]: *** [sub-jsc-pro-make_first-ordered] Error 2
make[1]: Leaving directory `/home/alan/Desktop/qtwebkit-opensource-src-5.6.1/Source/JavaScriptCore'
make: *** [sub-Source-JavaScriptCore-JavaScriptCore-pro-make_first-ordered] Error 2

Well, needless to say that I am calling it a day. :) In the end, I have got a working solution, so I am 'happy' to accept that I don't and might never understand why I need to export a new PKG_CONFIG_PATH rather than modify it 'inline'...