Difference between revisions of "Guidelines and HOWTOs/CMake/Frameworks"

*>Pippin
(Created page with "This tutorial will show you how to use a [http://api.kde.org/frameworks-api/frameworks5-apidocs/ KDE Framework] in a CMake-based project. It will introduce you to searching fo...")
 
*>Pippin
Line 10: Line 10:
 
Next, we search for the framework we want to use. We'll pick [http://api.kde.org/frameworks-api/frameworks5-apidocs/karchive/html/index.html KArchive], a framework for dealing with compressed file formats.
 
Next, we search for the framework we want to use. We'll pick [http://api.kde.org/frameworks-api/frameworks5-apidocs/karchive/html/index.html KArchive], a framework for dealing with compressed file formats.
  
  [http://www.cmake.org/cmake/help/v2.8.12/cmake.html#command:find_package find_package](KF5Archive)
+
  [http://www.cmake.org/cmake/help/v2.8.12/cmake.html#command:find_package find_package](KF5Archive REQUIRED)
  
Here, KF5Archive is the name of the package.
+
Here, KF5Archive is the name of the package. The exact result of this call will depend on the package, but at a minimum, we would expect the variable KF5Archive_FOUND to be set to TRUE if the package was found, and FALSE otherwise. Because we passed REQUIRED as an argument, CMake will exit with an error message if the package was not found in this case.
 +
 
 +
In the case of KF5Archive, we will get an ''imported target'' named KF5::Archive. Imported targets refer to libraries and executables external to the project, and include all the information you need to use them. So if you have an exectuable:
 +
 
 +
[http://www.cmake.org/cmake/help/v2.8.12/cmake.html#command:set set](tutorial_SRCS
 +
    main.cpp
 +
)
 +
[http://www.cmake.org/cmake/help/v2.8.12/cmake.html#command:add_executable add_executable](tutorial ${tutorial_SRCS})
 +
 
 +
you can start using KArchive just by linking against KF5::Archive:
 +
 
 +
[http://www.cmake.org/cmake/help/v2.8.12/cmake.html#command:target_link_libraries target_link_libraries](
 +
    tutorial
 +
    PRIVATE
 +
        KF5::Archive
 +
)
 +
 
 +
This will not only link against the KArchive library, it will set up the include paths properly as well. Don't worry about the PRIVATE keyword for now - it's only important when you are compiling a library.
 +
 
 +
To actually build this project, we'll need some C++ code to compile, so create a <tt>main.cpp</tt> file with the following:
 +
 
 +
#include <QCoreApplication>
 +
#include <KCompressionDevice>
 +
int main(int argc, const char**argv) {
 +
      QCoreApplication qapp(argc, argv);
 +
    KCompressionDevice dev("test.gz", KCompressionDevice::GZip);
 +
    dev.write("Hello world!\n");
 +
    return 0;
 +
}
 +
 
 +
Now you can build and run the test application, which should create a file named <tt>test.gz</tt> in your current directory.

Revision as of 10:50, 28 July 2015

This tutorial will show you how to use a KDE Framework in a CMake-based project. It will introduce you to searching for external packages in CMake, and linking to libraries provided by those packages.

This will assume a basic familiarity with CMake; if you are completely unfamiliar with CMake, you should check out the first CMake project tutorial.

We start off the CMakeLists.txt file with the lines any CMake project needs:

cmake_minimum_required(VERSION 2.8.12)
project(UsingFrameworksTutorial)

Next, we search for the framework we want to use. We'll pick KArchive, a framework for dealing with compressed file formats.

find_package(KF5Archive REQUIRED)

Here, KF5Archive is the name of the package. The exact result of this call will depend on the package, but at a minimum, we would expect the variable KF5Archive_FOUND to be set to TRUE if the package was found, and FALSE otherwise. Because we passed REQUIRED as an argument, CMake will exit with an error message if the package was not found in this case.

In the case of KF5Archive, we will get an imported target named KF5::Archive. Imported targets refer to libraries and executables external to the project, and include all the information you need to use them. So if you have an exectuable:

set(tutorial_SRCS
    main.cpp
)
add_executable(tutorial ${tutorial_SRCS})

you can start using KArchive just by linking against KF5::Archive:

target_link_libraries(
    tutorial
    PRIVATE
        KF5::Archive
)

This will not only link against the KArchive library, it will set up the include paths properly as well. Don't worry about the PRIVATE keyword for now - it's only important when you are compiling a library.

To actually build this project, we'll need some C++ code to compile, so create a main.cpp file with the following:

#include <QCoreApplication>
#include <KCompressionDevice>
int main(int argc, const char**argv) {
     QCoreApplication qapp(argc, argv);
    KCompressionDevice dev("test.gz", KCompressionDevice::GZip);
    dev.write("Hello world!\n");
    return 0;
}

Now you can build and run the test application, which should create a file named test.gz in your current directory.


This page was last edited on 28 July 2015, at 10:50. Content is available under Creative Commons License SA 4.0 unless otherwise noted.