How to run git commands when building a Qt App - c++

Scenario:
I am have a Qt App with a QtApp.pro some C++ code in main.cpp. To keep this question simple, please assume that it is a blank QtQuick2 app created from the QtCreator Application wizard.
Question:
Is it possible to run some Qt commands in the .pro files or C++ code in main.cpp?
What if I want to run this git command git rev-parse HEAD from my QtApp.pro or main.cpp and embed the commit ID somewhere on my UI to show the commit ID of the release? Is it possible? How?
Environment:
The Qt version I am running is Qt 5.9.3
Operating System : MacOS High Sierra

Is it possible to embed the command in pro file and access the pro file variable into an std::string?
To run command in pro file, this post, Running a program/script from QMake, shows you how to run script in .pro. I think you can write your git command in that script.
To access the pro file variable into an std::string.
you can transfer the file variable by -D option of gcc, which you can define it with QMAKE_CFLAGS in .pro file. this post, How to define a string literal in gcc command line? shows you how to use -D option.

You need to think separately of build time (includes compile-time) and run time. In general (think of some cross-compilation scenario, or just of a Qt application deployed on other computers) that could happen on different machines and on different days.
At run time, you could use QProcess to run some git command (or whatever program or script you need to run). Of course, you need git to be installed, and perhaps your source code tree to be available at run time (on a deployed and installed Qt application, that might not be the case by default; for example most Qt applications on my Linux distribution are not installed with their source code tree).
At build time, on Unix-like machines, a .pro Qt project file is generating a Makefile which is used by make for build. That Makefile could contain git commands. See _timestamp.c target of this Makefile (not using Qt so hand-written, not generated by qmake) as an example; it contains details about the current git commit.
How to configure qmake to generate custom commands in the Makefile is a different question; you might add custom targets.

Related

How to generate a C++ executable file on Clion (using Ubuntu)

I'm currently learning C++ and I'm working on a small project. I was wondering how I can generate an executable of my project. I'm not sure how to do it, I'm using Ubuntu 20.04
I've googled it but I can not find any instructions on how to do it.
Well. If you are using CLion, you can just create a new project, and check the CMake file that CLion generate. Something like this:
cmake_minimum_required(VERSION 3.20)
project(Test)
set(CMAKE_CXX_STANDARD 14)
add_executable(Test main.cpp)
And in that file there was a line with a function called add_executable, in that function you set first the exe name and then the source files. And just run the project in CLion. By default CLion create a directory calle "cmake-build-debug" where the exe file are located.
If you want to add more libraries, change the binaries source directory and more. You will need learn CMake. Also you can use CMake standalone whiteout CLion, you just need install it sudo apt-get install cmake and use then in the terminal.
Expanding over #Steback's answer:
First, a clarification: an executable file is a file that can be executed by the system. It (roughly) contains assembly commands. Under Windows executable files are marked with an .exe extension. Under linux, they are usually extension-less.
To generate an executable file from C / C++ code you ("only") need a C/C++ compiler. A default / pre-installed one on Ubuntu is gcc / g++ (whereas on Windows you need to actively install one).
CLion is an IDE and (exactly like any other IDE) can run the compiler for you. IDE (stands for Integrated Development Environment) is a program which incorporates (minimally) a text/code editor, a compiler and a debugger (all of which it invokes normally via command line, just as you can do yourself).
CLion is an advanced (and excellent) IDE. In CLion, the way you specify how exactly it should invoke the compiler is via the CMake language (not to be confused with the unix tool make which chiefly only knows to run commands conditionally on file modified date).
CMake code should be placed in a file named CMakeLists.txt in the project root directory (sometimes CLion creates this file for you automatically). A minimal cmake project looks like
# Specify cmake language version to use for this file
cmake_minimum_required(VERSION 3.10)
# Specify any name for the project
project(NameYourProject)
# A name for your executable file and the code files needed to build it
add_executable(YourExecutableName source_file1.cpp somefolder/source_file2.cpp header_file.h)
Of course this is just a very minimal example. The CMake language is a powerful language to specify build processes, with cross-platform support. You can look it up / learn it someday.
When giving the "build" command to CLion it will now do two things:
use the cmake tool to generate a set of commands for gcc/g++ (this is called "cmake configure" + "cmake generate") - according to what you wrote in CMakeLists.txt
run the generated commands to hopefully build your executable.
As a beginner, you may be better off first trying to run the compiler yourself via the command line to see what it does. You can also opt for a different IDE (e.g. CodeBlocks, eclipse, Dev C++) where you specify what you need the compiler to do via a GUI and not via CMake (although CMake is arguably more convenient).
I'm using Dev C++. When I run and compile it, it automaticcally generate a .exe file. Just install it and open ur file with it and compile it. Should work good.

How can we apply versioning to executable/binaries in C++?

I have a big C++ application which we are compiling through Jenkins and generating zipped artifacts containing binaries, headers, config and other relevant files. The build is deployed in the form of services on the client. The problem is how can apply version on those binaries to keep a tract of which build is deployed on which client?
Like with earlier C# application we used make changes to AssemblyVersion file with the tags that we apply on GIT and then compile and we could see the executable have the version applied. Is there a way to do the same in C++?
We are using CMakeLists.txt file for generating builds. We have linux based environment (CentOS 7.5) the application is developed in C++.
Thanks in advances!
Since you're using CMake, what you can do is use the configure_file() function in your CMakeLists.txt to create a C++ source file which includes your Git version information as a string, then include the created file into your target.
You can get the Git version information into a CMake variable by calling the git executable from CMake, although there are prewritten modules out there to do the heavy lifting.
You can then use the command-line strings and grep tools to find the version string in the binary, or some other method to get it programmatically, depending on if you're making an executable or library.

Where do I get the qm executable from?

I am working on an Ubuntu 16.04 system and tried to compile an application with the qm command as per the readme file in the source directory. When I try to run the command I get the repose:
$ qm
qm: command not found
This suggests that my Ubuntu PC does not have a repository with a package that supplies a qm executable setup. I guess the source code for the tool may be available somewhere and be usable for multiple GNU Linux operating systems.
How do I source and install the qm executable?
The readme file for the code I am trying to compile states that qm stands for quick-make or QMake but I cannot find any reference to these in a google search. I only find references to Qt's qmake which is not the tool I am looking for based on the errors I get back.
This qm tool uses a defs.mk file as its instruction set.
The program I am trying to install uses the RAVL Library. The README file for that library also mentions qm command.
I found a source for the qm or QMake or Quick Make tool. In the Recognition And Vision Library (RAVL) Installation Instructions the installation of QMake is mentioned.
Building the RAVL library requires the use of an ANSI C++ compiler
along with the GNU make utility (or another compatible version of
make). The RAVL build process is actually managed by the QMake
utility. QMake is a flexible compilation aid, designed to provide a
simpler interface to the GNU make program. As part of the RAVL
installation process, a copy of QMake will be configured and
installed.
The instructions go on to explain that by; obtaining a copy of the RAVL source code, configuring, making and installing it you get both the RAVL libary and the quick-make tool set. This includes the qm command.
After preforming the following steps:
git clone -b tested_nightly git://git.code.sf.net/p/ravl/ravl ravl
cd ravl
./configure
make
sudo make install
I am able to use the qm command.

How to compile qtwebkit in qt-5.8

I have compiled QT-5.8 from github successfully, each submodule is cloned by init-repository provided by QT. However, in Qt5.8, it has removed qtwebkit.
But my app needs qtwebkit, so I clone qtwebkit submodule and qmake it.
However, it shows the compilation errors
( test -e Makefile.api || /usr/local/Qt-5.8.0/bin/qmake -o Makefile.api /home/tumh/qt5/qtwebkit/Source/api.pri ) && make -f Makefile.api
make[1]: Entering directory '/home/tumh/qt5/qtwebkit/Source'
make[1]: *** No rule to make target '/home/tumh/qt5/qtwebkit/Source/WebCore//libWebCore.a', needed by '../lib/libQt5WebKit.so.5.8.0'. Stop.
make[1]: Leaving directory '/home/tumh/qt5/qtwebkit/Source'
Makefile:40: recipe for target 'sub-api-pri-make_first-ordered' failed
make: *** [sub-api-pri-make_first-ordered] Error 2
I have no idea that how to compile a single submodule in QT.
Any suggestion is appreciated.
thanks!
You should take tarball of webkit from official releases. It should build fine with Qt-5.8.
The following describes how to compile qtwebkit module so it is usable with Qt 5.9.9. I assume the process is similar if not identical for Qt 5.8.
An overview of the process
All of the required components should be compiled using one tool chain. I suggest using the one installed with Qt.
You gonna need ICU compiled, the source code can be obtained from the official site.
The source code of qtwebkit module that we want to compile is available here (thx #J. Doe for the link!)
Regardless of the operating system you are working on, in order to compile qtwebkit module you gonna need the following additional tools:
ruby
gperf
flex
bison
python 2
Qtwebkit module depends on declarative module. It becomes available when qtquick1 is installed.
It is assumed that Qt 5.9.9 is installed. I was using these installers.
The process takes some time so if you need the module ready ASAP go to the last section (What if you cannot perform some of the above steps).
Compiling on Windows (tested on Win10)
On Windows I recommend using chocolatey to install additional tools.
Compiling ICU
Install msys2 package via chocolatey. It allows to use the scrips provided with ICU source code with very few modifications.
Installation script requires make program available. It doesn't matter if mingw32-make is virtually (of even literally) the same tool. Copy mingw32-make.exe and rename it to make.exe.
Using cmd with integrated mingw tools (installed along with Qt) open msys2 shell forwarding the PATH variable.
msys2_shell -use-full-path
Go to the ICU source code directory (mine was C:\icu\source) and run
./runConfigureICU MinGW -prefix=$PWD/../dist
(It is expected to encounter "unknown platform" issue, no worries)
Now run:
gcc -dumpmachine
Save the output, in my case it was i686-w64-mingw32.
Using this result execute:
./configure -build=i686-w64-mingw32 -prefix=$PWD/../dist
(modify build parameter according to the result of the previous step)
Now, you should be able to compile ICU with:
make & make install
(If you want to speed things up you can engage multiple CPU cores in the above process. For example in order to engage 777 cores execute make -j777 & make install)
Assuming your ICU source code was in C:\icu\source directory, the result of the compilation should be in C:\icu\dist.
Compiling qtwebkit module
As said in the first section, compiling qtwebkit module requires additional tools.
They can be installed via chocolatey using the following command:
choco install ruby gperf winflexbison python2
This, among others, installs win_flex.exe and win_bison.exe. As of this writing these executables are located (at least in my case) in C:\ProgramData\chocolatey\lib\winflexbison\tools .
The qmake checks for programs named bison.exe and flex.exe. So I have copied both win_flex.exe and win_bison.exe and renamed them flex.exe and bison.exe accordingly.
The last step is to add both of these programs to PATH variable.
To do so execute (in cmd with integrated mingw tools) the following command:
set PATH=C:\ProgramData\chocolatey\lib\winflexbison\tools;%PATH%
Additionally you need to point to the directory where includes and libs of compiled ICU are located. I have done it like this:
set PATH=C:\icu\dist\bin;%PATH%
set INCLUDE=C:\icu\dist\include;
set LIB=C:\icu\dist\lib;
Above assumes that prior to executing this commands there was no variables named INCLUDE and LIB set in the currently used cmd.
Finally, qmake process checks for a variable named SQLITE3SRCDIR.
As suggested by this answer you can set it to sqlite sources provided with Qt. In my case it was done like this:
set SQLITE3SRCDIR=C:\Qt\Qt5.9.9\5.9.9\Src\qtbase\src\3rdparty\sqlite
Now (using the same cmd) go to the directory where Qt sources are located and execute configure.bat. I have done both of these steps with:
cd C:\Qt\Qt5.9.9\5.9.9\Src
configure.bat
Finally, extract the downloaded source code of the qtwebkitmodule to the sources directory of Qt (C:\Qt\Qt5.9.9\5.9.9\Src in my case) and make a module. I have done it like this:
cd qtwebkit-opensource-src-5.9.0
mkdir build
cd build
qmake -r ..
make
make install
It is strongly recommended to utilize multiple cores in the make process, otherwise prepare yourself for a very long compilation.
Now you should be able to use webkit and webkitwidgets in your Qt projects.
Compiling on Linux (tested on LUbuntu 18.04)
I suggest using compilation tools provided with Qt instead of default make and g++ compiler. To do so I have exported path to the tools provided with Qt like this:
export PATH=/home/$USER/Qt5.9.9/5.9.9/gcc_64/bin/:$PATH
You gonna need ICU compiled. I suggest using version 56.1 as it is the same shipped with Qt 5.9.9. The compilation process is almost identical as it was described for Windows. the only difference is that you run:
./runConfigureICU Linux/gcc --prefix=$PWD/../dist
and later configure script can be omitted on Linux.
On lUbuntu 18.04 I needed the following packages installed:
apt-get install ruby bison gperf python flex perl libx11-dev xserver-xorg-dev xorg-dev libpulse-dev libsqlite3-dev
As with compiling qtwebkit on Windows, you gonna need qtquick1 module installed.
I have encountered an error saying that some headers related to OpenGL were missing. If you have the same problem then in my case installing libgl1-mesa-dev package solved it.
Now extract source code of qtwebkit module sources directory of your Qt installation. In my case it was "/home/$USER/Qt5.9.9/5.9.9/Src".
Modify WTF.pri file and add the path to ICU includes and libs after the first INCLUDEPATH. In my case it was done like this:
...
INCLUDEPATH += /home/$USER/icu/dist/include/
LIBS += -L/home/$USER/icu/dist/lib/
...
Note '-L' is placed before path pointing to libs.
Now you should be able to compile qtwebkit module in usual manner:
mkdir build
cd build
qmake -r ..
make & make install
What if you cannot perform some of the above steps
You can always try to use prebuild binaries:
https://download.qt.io/snapshots/ci/qtwebkit/5.9/latest/qtwebkit/
or unofficial fork of the qtwebkit module:
https://github.com/qtwebkit/qtwebkit/releases

How to run qmake from the static Qt

For making a very simple Qt app "installable" on other systems, I'm using Qt Installer Framework following this link.
In bottom, in Setting up Qt Installer Framework, number 1 orders to have Qt Installer Framework source code. I downloaded it from here. (qt-installer-framework-opensource-2.0.1-src.zip)
Now I don't understand the next instruction there :(
It says:
2- Build the tools by running the "qmake" from the static Qt, followed by "make" or "nmake".
My question is, first what does it mean?
And from what path?
I don't know how to do it:(
qmake comes with the qt-framework and is a make file generator. (an alternative to cmake).
You call qmake on a .pro file from your project. This .pro file have to contain your source code files project dependencies and more.
Consider that you have a project folder with your source code and the .pro file. Then you call the qmake command in this folder. qmake is an program itself, which you can find in the bin folder of your qt-installation. If qmake is in your path variable, you go to the terminal, navigate to the specific folder and just write:
qmake
After that qmake will create a makefile. Then you could call makeand your program will be build.
I hope my answer helps you. You can learn more about qmake on the website of Qt. Here is also a very good qmake tutorial: klick
edit:
how to call make on windows:
download and install cygwin from
http://www.cygwin.com/setup-x86.exe - 32 bit installer or
http://www.cygwin.com/setup-x86_64.exe - 64 bit installer.
then start the Cygwin terminal (Cygwin.bat) and navigate to your folder and call
make
and that will build your qt-installer!