Console Applications

[jsulm]

@tomy "As an out of scope question: do you return the base of CMD (DOS OS) to Unix?" - what does it mean? What is base?

Writing a simple CLI C++ app without IDE in a terminal (CMD):

• Use an editor to write your cpp file (for example vim or what ever): vim myapp.cpp
• Then call the compiler: g++ -o myapp myapp.cpp
• Then start your app: ./myapp
  That's all for a simple app.
  In Qt creator you can see what it does if you press CTRL-R in "Compile Output" tab: it uses only CLI tools, like qmake, compiler (for example g++), linker,...

Console apps are not only important on UNIX/Linux/MacOS but even on Windows. You need them for example to write scripts, build software,...

[ambershark]

@tomy @jsulm's example is perfect for linux but since I know you don't know linux yet and are using windows I'll give you the same thing for windows:

Launch a cmd and do the following:

> mkdir test
> cd test

create a main.cpp with somthing like:
#include <iostream>

using namespace std;

int main()
{
   cout << "hello world" << endl;
   return 0;
}

> qmake -project
> qmake
> mingw32-make
> test.exe

This assumes you have /path/to/qt/bin in your path variable in order to use and access qmake. It also assumes you have mingw32 compiler installed. If not substitute compilation command mingw32-make for whatever compiler you have.

This is a great example of where linux is easier than windows on a command line (from our other thread). There is no real additional setup in linux, all the stuff @jsulm wrote works right out of the box.

Edit: Explaining some of the commands --

qmake -project Will create you a test.pro file. This is only done once to bootstrap your project file. After that you modify that .pro file to add the things you need.

qmake evaluates the project file and creates a makefile for you.

mingw32-make invokes the make program for the mingw compiler. This will execute the Makefile that was generated when you ran qmake and build your application using mingw32-g++, and other pieces it needs to compile and link.

[tomy]

Thank you very much.
One question:

"> test.exe"

Why should we have a test.exe file?

[mrjj]

@tomy
Hi
The test.exe comes from the executing the real makefile as neatly explained
in section "mingw32-make " :)

[tomy]

Hi,

I asked because I don't have that file in the test folder!

[mrjj]

@tomy
Well do you see .o file ? Maybe there is a build folder one level up?
If not, then show the log (text) you get from running mingw32-make (step)
Maybe there is compile or link error as that would do that no .exe is created.

Ah, sorry. Its in the release folder

[ambershark]

Oops sorry I forget that in windows things like Release/ and Debug/ folders. :)

[mrjj]

@ambershark
Well i had to follow the sample and see. Was not sure what would really happen :)

[ambershark]

@mrjj Lol. I'm glad it actually worked since I just typed that out without testing anything. And I don't use windows much so I could easily have messed it up. :)

[tomy]

Sorry there isn't such a file an any folder there:

[jsulm]

@tomy Maybe it is just called differently? So, is there ANY *.exe file?
Also, if you build in CMD you actually will see which files are generated. Did you check?

[tomy]

Look, I did these:
Creating a C++ file named "main" with a simple code in it, in the "test" folder.
Then, found and ran all three commands (qmake -project, qmake, mingw32-make).
And the result as shown above (with no ".exe" file in the "test" folder.
I CMD:

[jsulm]

@tomy As you cen see the build failed, that's why there is no exe.

[jsulm]

@tomy Looks like g++ is not found.
Try to add the bin directory of your MinGW installation to PATH and try again.

[mrjj]

Hi
An alternative to fiddling with path is to run the
c:\Qt\5.8\mingw53_32\bin\qtenv2.bat
in the cmd before trying to compile.

[tomy]

@mrjj

Hi
An alternative to fiddling with path is to run the
c:\Qt\5.8\mingw53_32\bin\qtenv2.bat
in the cmd before trying to compile.

Hi,
"The system cannot find the path specified."
Anyway, it's not that important and we can leave it out because it's not my purpose to be familiar with running files from CMd, now. Maybe when needed.
(I liked to test that simple example this way but, the testing may not be so easy) Thanks.

[jsulm]

@tomy Depending on the MinGW version you install the path can be a bit different. Just search for qtenv2.bat file in your Qt installation directory.

[tomy]

Yes, I did it and I think the system is set now and ready for the next tests. You can look at this:

"text.exe" exists but nothing is shown after test.exe in CMD.

Update:
After re-opening the CMD and testing the .exe:

[Flotisable]

@tomy
what code you write in test?

[Eeli K]

@tomy Locate the libgcc_... file on your system and copy it to the same directory with the exe. Or set the PATH variable. See http://stackoverflow.com/questions/4702732/the-program-cant-start-because-libgcc-s-dw2-1-dll-is-missing.