Re: [CMake] Problem with creating shared library

Damir Porobic Sun, 26 Aug 2018 04:51:03 -0700

Ok, I've found the issue for the latest problem but I'm not sure how to fix it 
in the CMake file. The make was using an old version of 
/usr/local/lib64/libkImageAnnotator.so.0.0.1 so I removed everything with 
kImageAnnotato in its name from this directory and run again the sudo make 
install which gave me this output



-- Install configuration: "Debug"
-- Up-to-date: 
/usr/local/lib64/cmake/kImageAnnotator/kImageAnnotator-config.cmake
-- Up-to-date: 
/usr/local/lib64/cmake/kImageAnnotator/kImageAnnotator-config-version.cmake
-- Up-to-date: 
/usr/local/lib64/cmake/kImageAnnotator/kImageAnnotator-targets.cmake
-- Up-to-date: 
/usr/local/lib64/cmake/kImageAnnotator/kImageAnnotator-targets-debug.cmake
-- Installing: /usr/local/lib64/libkImageAnnotator.so
-- Set runtime path of "/usr/local/lib64/libkImageAnnotator.so" to 
"/usr/local/lib64"
-- Up-to-date: /usr/local/include/kImageAnnotator
-- Up-to-date: /usr/local/include/kImageAnnotator/KImageAnnotator.h
-- Up-to-date: /usr/local/include/kImageAnnotator/KImageAnnotatorExport.h


So only libkImageAnnotator.so is created and installed, but not the one with 
the version at the end which cmake seems to expect: in my test project

CMake Error at 
/usr/local/share/kImageAnnotatorConfig/cmake/kImageAnnotatorConfig.cmake:79 
(message):
  The imported target "kImageAnnotator" references the file

     "/usr/local/lib64/libkImageAnnotator.so.0.0.1"

  but this file does not exist.

When I manually create a link to the installed file:

$ sudo ln -s /usr/local/lib64/libkImageAnnotator.so 
/usr/local/lib64/libkImageAnnotator.so.0.0.1

Everything finally works, but I need to fix this final issue with the missing 
link. This was working earlier I think.


________________________________
From: Damir Porobic <damir_poro...@live.com>
Sent: Friday, August 24, 2018 9:37:30 PM
To: Sebastián Mancilla
Cc: cmake@cmake.org
Subject: Re: [CMake] Problem with creating shared library


I've fixed both issues, the second by implementing the pimpl idiom but still I 
can't used the library in the other project, again I get the error with 
undefined reference to the constructor (and a method that I've added):


[ 75%] Linking CXX executable testApp
CMakeFiles/testApp.dir/main.cpp.o: In function `main':
/home/dporobic/projects/testApp/main.cpp:9: undefined reference to 
`KImageAnnotator::KImageAnnotator(QPixmap const&)'
/home/dporobic/projects/testApp/main.cpp:11: undefined reference to 
`KImageAnnotator::testMethod()'
collect2: error: ld returned 1 exit status

But the constructor and the method don't seem to be private anymore:

dporobic@linux ~/projects/kImageAnnotator/build (sharedLibTestBranch)
$ nm -g lib/libkImageAnnotator.so | c++filt | grep "::testMethod\|::KImage"
0000000000014f08 T KImageAnnotator::testMethod()
0000000000014b18 T KImageAnnotator::KImageAnnotator(QPixmap const&)
0000000000014b18 T KImageAnnotator::KImageAnnotator(QPixmap const&)

Also, after the constructor call and before the call to the test method in my 
test project, there is a call to an inherited method (show()) from QWidget and 
the linker is not complaining about this one:

auto kImageAnnotator = new KImageAnnotator(pixmap);
kImageAnnotator->show();
kImageAnnotator->testMethod();


________________________________
From: Sebastián Mancilla <smanc...@jlab.org>
Sent: Thursday, August 23, 2018 22:13
To: Damir Porobic
Cc: cmake@cmake.org
Subject: Re: [CMake] Problem with creating shared library

I forgot to update the include path in the patch I sent you.

It should be like this (note that it contains just "include", not 
"include/kImageAnnotator"):

target_include_directories(kImageAnnotator
        PUBLIC
        $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/include>
        $<BUILD_INTERFACE:${CMAKE_BINARY_DIR}/include>
        $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
        )

And kImageAnnotator.h should change the export include to:

#include "kImageAnnotatorExport.h"


You still have a bigger problem, though. kImageAnnotator.h is including private 
headers

#include "../../src/gui/VisibilitySwitcher.h"
#include "../../src/annotations/core/AnnotationArea.h"
#include "../../src/backend/Config.h"
#include "../../src/widgets/ToolPicker.h"
#include "../../src/widgets/ColorPicker.h"
#include "../../src/widgets/SizePicker.h"
#include "../../src/widgets/FillPicker.h"

If those are required by your clients, then they should be in the 
"include/kImageAnnotator" directory and installed along with 
"kImageAnnotator.h".
Otherwise, consider using the pimpl idiom and remove the includes from the 
public header.


El mié., 22 de ago. de 2018 a la(s) 17:08, Damir Porobic 
(damir_poro...@live.com<mailto:damir_poro...@live.com>) escribió:

Thanks you Sebastián for finding the issue and fixing the CMake, probably would 
have never found out that it was set to private.


The kImageAnnotator-example is working now as expected. Do I need something 
else, except installing the lib, in order to use it in different projects? I've 
created a second project which is identical to the kImageAnnotator-example but 
I get following when I try to build it:


[ 50%] Building CXX object CMakeFiles/testApp.dir/main.cpp.o
In file included from /home/dporobic/projects/testApp/main.cpp:2:0:
/usr/local/include/kImageAnnotator/KImageAnnotator.h:31:35: fatal error: 
KImageAnnotatorExport.h: No such file or directory
 #include <KImageAnnotatorExport.h>
                                   ^
compilation terminated.


The includes look like this:

#include <QApplication>
#include <kImageAnnotator/KImageAnnotator.h>


And the CMake looks like this:

find_package(kImageAnnotator REQUIRED)

add_executable(testApp main.cpp)
target_link_libraries(testApp kImageAnnotator)


Am I missing something again?


________________________________
From: Sebastián Mancilla <smanc...@jlab.org<mailto:smanc...@jlab.org>>
Sent: Wednesday, August 22, 2018 00:51
To: Eric Noulard
Cc: Damir Porobic; cmake@cmake.org<mailto:cmake@cmake.org>
Subject: Re: [CMake] Problem with creating shared library

I fixed your problem. Get the attached patch and apply it with "git apply 
<patch_file>".

The kImageAnnotator constructor was private to the library (I just learned that 
Qt does that when creating shared libraries), and that's why you get the 
undefined reference error. You could have checked it with:

nm lib/libkImageAnnotator.so | c++filt | grep ::KImage
00000000000141f6 t KImageAnnotator::KImageAnnotator(QPixmap const&)
00000000000141f6 t KImageAnnotator::KImageAnnotator(QPixmap const&)

The "t" shows it is private.

You have to set the proper export macros to make it visible:

https://wiki.qt.io/How_to_create_a_library_with_Qt_and_use_it_in_an_application<https://urldefense.proofpoint.com/v2/url?u=https-3A__wiki.qt.io_How-5Fto-5Fcreate-5Fa-5Flibrary-5Fwith-5FQt-5Fand-5Fuse-5Fit-5Fin-5Fan-5Fapplication&d=DwMFAw&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=8hmSv9ww5s9qu3iT8h5WMi8-YcKXaJvelxT3fMih7S4&m=y6-B01YTd3TICi74QxO0LfDQVtz1m7fckmS3ItKkAmE&s=WmSjv8Q5QDreoWKNX4mS9hZm6lMR1pfhmDpjVug9nKU&e=>
http://doc.qt.io/qt-5/sharedlibra
<https://urldefense.proofpoint.com/v2/url?u=http-3A__doc.qt.io_qt-2D5_sharedlibrary.html&d=DwMFAw&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=8hmSv9ww5s9qu3iT8h5WMi8-YcKXaJvelxT3fMih7S4&m=y6-B01YTd3TICi74QxO0LfDQVtz1m7fckmS3ItKkAmE&s=I_GD4gkI-8u5o_gjXOD-wZKguDdfF2Gu4YG3Swst3hY&e=>
How to create a library with Qt and use it in an 
application<https://urldefense.proofpoint.com/v2/url?u=https-3A__wiki.qt.io_How-5Fto-5Fcreate-5Fa-5Flibrary-5Fwith-5FQt-5Fand-5Fuse-5Fit-5Fin-5Fan-5Fapplication&d=DwMFAw&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=8hmSv9ww5s9qu3iT8h5WMi8-YcKXaJvelxT3fMih7S4&m=y6-B01YTd3TICi74QxO0LfDQVtz1m7fckmS3ItKkAmE&s=WmSjv8Q5QDreoWKNX4mS9hZm6lMR1pfhmDpjVug9nKU&e=>
wiki.qt.io
This tutorial illustrates different approaches for using a custom library in 
your application on Windows. The first part explains how to create a shared 
library and how to link against it in your application. The second part is 
about creating and using a static library. Creating a shared library ...

ry.html

The patch does that, and now the example links with the library just fine. The 
kImageAnnotatorExport.h header defines the macro, the compile definition is set 
for the shared library target in the CMakeLists.txt. I guess you'll  have to do 
the same for all classes used by the unit tests, no sure of the Qt development 
practices.

I also reworked your CMake files a bit. I am sending a single patch, though. 
Sorry.


El mar., 21 de ago. de 2018 a la(s) 14:29, Eric Noulard 
(eric.noul...@gmail.com<mailto:eric.noul...@gmail.com>) escribió:


Le lun. 20 août 2018 à 19:05, Damir Porobic 
<damir_poro...@live.com<mailto:damir_poro...@live.com>> a écrit :

Hi Eric,


yes, this is the project. I have pushed my current state to this branch 
https://github.com/DamirPorobic/kImageAnnotator/tree/sharedLibTestBranch<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_DamirPorobic_kImageAnnotator_tree_sharedLibTestBranch&d=DwMFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=8hmSv9ww5s9qu3iT8h5WMi8-YcKXaJvelxT3fMih7S4&m=r4LA5jjr_jrRNhddqyy5IsuqRRwHEPCwRMFbxoU1ChI&s=j_vYMAeNlkSJPzPWt5eGGRXiqm4RocWUGgyctA8SGE4&e=>


I've tried also without the generate_export_headers (cleaned everything up 
before trying out) but I get the same result.


KImageAnnotator::KImageAnnotator(QPixmap const&)should be exposed by the 
handwritten file, that's true, I think I got something mixed up there and I 
don't actually need the generate_export_headers, but as said, even without the 
line, it's not working.

I'm quite lost with the file layout.

in example/main.cpp you do:
#include <kImageAnnotator/KImageAnnotator.h>
so I guess you expect that
target_link_libraries(kImageAnnotator-example PRIVATE 
kImageAnnotator::kImageAnnotator)

will bring you the include path to "kImageAnnotator/KImageAnnotator.h" along 
with the [imported] target

in your main tree (not in example) there is a trick because you did:

add_library(kImageAnnotator::kImageAnnotator ALIAS kImageAnnotator)

and then in the test directory you do:

target_link_libraries(${UnitTestName} Qt5::Test kimageannotator_LIB)

with

add_library(kimageannotator_LIB STATIC ${kimageannotator_SRCS})

so AFAIU you compile your kImageAnnotator library twice. Once for building the 
target you expect to use in example/ subdir
and another time as a STATIC lib for the unit test. So the unit test is not 
linking to the same object lib at all ??

I am not used to KDE development but all this seems very fuzzy to me.

May be you could get more precise help from people who know better about KDE 
dev and the specific CMake machinery that comes along
like ECM 
(https://github.com/KDE/extra-cmake-modules<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_KDE_extra-2Dcmake-2Dmodules&d=DwMFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=8hmSv9ww5s9qu3iT8h5WMi8-YcKXaJvelxT3fMih7S4&m=r4LA5jjr_jrRNhddqyy5IsuqRRwHEPCwRMFbxoU1ChI&s=LaNKLek4ewlsoy7ECnW4qRmkBAAVUeo6iTSFqsT9ACo&e=>)
 you seems to be using.

--
Eric


--
Sebastian Mancilla Matta
CCTVal, UTFSM
Valparaíso, Chile


--
Sebastian Mancilla

-- 

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Re: [CMake] Problem with creating shared library

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