0.9 — Configuring your compiler: Build configurations

A build configuration (also called a build target) is a collection of project settings that determines how your IDE will build your project. The build configuration typically includes things like what the executable will be named, what directories the IDE will look in for other code and library files, whether to keep or strip out debugging information, how much to have the compiler optimize your program, etc… Generally, you will want to leave these settings at their default values unless you have a specific reason to change something.

When you create a new project in your IDE, most IDEs will set up two different build configurations for you: a release configuration, and a debug configuration.

The debug configuration is designed to help you debug your program, and is generally the one you will use when writing your programs. This configuration turns off all optimizations, and includes debugging information, which makes your programs larger and slower, but much easier to debug. The debug configuration is usually selected as the active configuration by default. We’ll talk more about debugging techniques in a later lesson.

The release configuration is designed to be used when releasing your program to the public. This version is typically optimized for size and performance, and doesn’t contain the extra debugging information. Because the release configuration includes all optimizations, this mode is also useful for testing the performance of your code (which we’ll show you how to do later in the tutorial series).

When the Hello World program (from lesson 0.7 -- Compiling your first program) was built using Visual Studio, the executable produced in the debug configuration was 65kb, whereas the executable built in the release version was 12kb. The difference is largely due to the extra debugging information kept in the debug build.

Although you can create your own custom build configurations, you’ll rarely have a reason to unless you want to compare two builds made using different compiler settings.

Best practice

Use the debug build configuration when developing your programs. When you’re ready to release your executable to others, or want to test performance, use the release build configuration.

Switching between build configurations

For Visual Studio users

There are multiple ways to switch between debug and release in Visual Studio. The easiest way is to set your selection directly from the Solution Configurations dropdown in the Standard Toolbar Options:

VS Solution Configurations Dropdown

Set it to Debug for now.

You can also access the configuration manager dialog by selecting Build menu > Configuration Manager, and change the active solution configuration.

For Code::Blocks users

In Code::Blocks, you should see an item called Build Target in the Compiler toolbar:

Code::Blocks Build Target Dropdown

Set it to Debug for now.

0.10 -- Configuring your compiler: Compiler extensions
0.8 -- A few common C++ problems

121 comments to 0.9 — Configuring your compiler: Build configurations

  • Manuel Calzadillas

    One lesson per day,
    Hope to end this tutorial soon lol
    Thanks Alex

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  • Nish

    What's the difference between a makefile and a build configuration? (I know makefiles are an advanced-level concept - I'm just curious)

    • A makefile usually stores a bunch of commands related to compilation, which usually is compiling many files them linking them together, and other stuff. The build config is just a compiler option that specifies if the program should be optimized or not while building.

  • J34NP3T3R

    Problem here. on DEBUG mode compile the script paused but on RELEASE compile i run the HelloWorld.Exe and it closes immediately.

  • yeokaiwei

    Hi Alex,
    There's a potential bug that's been caused by the tutorial configuration in Microsoft Visual Studio 2019.

    I've added the link below.

    It works fine on the default configuration

    Configuration setting
    1. Change the Warning Levels to 4
    2. Treat all Warning as Errors
    3. Change the C++ Standard to C++2017
    4. Change the C Standard to C++2018

  • Hey everyone,
    So far I've compiled and ran, with and without debugging the Hello World program, using Ctrl-F5 on Virtual Studio 2019 on my Win10 machine and works perfectly both on Debug and Release config. However I wanted to test whether I could just run the exe files by finding them on the file explorer (as we'd usually do with programs downloaded from the internet etc) and exe file just runs and blinks out in a flash. Is that something I should be fixing by now or is it just covered on the next tutorials?

    PS. I always get this after the message appearing on console " C:\Users\??????\source\repos\HelloWorld\Debug\HelloWorld.exe (process 17416) exited with code 0." is that ok?

    Thanks very much,

    • Dila

      Yeah, I get the same thing. I've watched other tutorials and this just seems to happen when you are using the console. It's probably fine, but if you were still worried about it you could try looking on GitHub, stack overflow, Reddit, or just googling it.

  • DJ

    I am able to develop an exe of console application(with CodeBlock) in release config, but it is not showing "Hello, world" after trying to execute; it throws "The applcation was unable to start correctly(0xc000007b)" in win10 os. Any help please?

    • DJ

      sorry, I forgot to mention it's working fine in debug config, I don't know how to config(properly) in release mode, can you please give few tips regarding release config? Thanks a lot for creating a site like this one and even more for the fact that it's being actively maintained and comments responded. May God bless for the effort taken!

      • dj

        One thing I have observed is that it(release mode generated exe) works when run by cb_console_runner.exe(build and run option in codeblock) but not directly(double clicking the file)! Any clues?

        • dj

          Funny, I had changed the compiler to clang and had built in release mode and it worked!!!(Don't know if clang is a mature alternative and if there would rise any other unanticipated problems)

  • Aaron

    On the previous page the graphic showed the program saying "Hello, world!" and then it just says press any key to close this window, but I get a third line in between those two:

    "C:\Users\buffa\source\repos\HelloWorld\Debug\HelloWorld.exe (process 17064) exited with code 0."

    What does this mean and is it something I should be concerned about?

    I'm using Microsoft Visual Studio on Windows.

  • debugging information

    What does debugging information mean in the following sentence?

    The difference is largely due to the extra debugging information kept in the debug build.

    • Alex

      See and for some more information.

  • Rmj,

    Hello,im on visual studio and i cant seem to find a solution configuration button, what do i do

  • Shiba

    I think it would be great and much appreciated if you guys can update the whole IDE configuration part with Visual Basic Code examples as well. Thank you for all the continuous effort so far.

    • Inu

      I think you meant to say 'Visual *Studio* Code' here. I concur with your suggestion, however, my guess as to the reason they don't have a bunch of different compiler/IDE stuff is because 1) they *do* have the options for a few really popular compilers/IDEs. And 2) I believe (but I'm not sure since I haven't looked ahead) they only talk about the specifics of compiling and IDE stuff in these early lessons. So once you get past them it won't make a difference which compiler/IDE you're using.

    • nascardriver

      Visual Studio Code isn't an IDE, it's a text editor. You invoke the compiler manually, in which case you can follow the instructions about gcc. Or you use a plugin to invoke the compiler, then you need to search for instructions of that plugin.

  • Vitaliy Sh.

    The trouble with the images here

    When a 1680:1050 monitor is split between a web browser (attached left), and a text editor (attached right), i'm experience a trouble.

    I'm can't see the whole images from <div>s "For Visual Studio users" and "For Code::Blocks users", and also can't scroll them side-wise, to see more.

    Q: Can your, please, fix it?
    Proposal: <pre> tag (tested on my mobile, no breakage), or cropping.

    • Alex

      I tried to fix it in a slightly different way. Let me know whether it works for you.

      • Vitaliy Sh.

        The new look of the site is great on my halved desktop browser. Wide and convenient. Thanks, sir.
        For a quite a few days before, and today: Everything is works.
        But the mobile version (~4.7") need to be zoomed a lot, for me to see the diagram's letters. Your rather will be unable to fix it ;)

  • Vitaliy Sh.

    There is no reference about using g++'s -g flag here, to match the lesson's 0.7 "If you're using g++ on the command line".

    Maybe remove it from 0.7, because:
    1) The "Yes, but we don't recommend it for beginners." from 0.6
    2) The man for g++ -g looks rather arcane. My IDE default to -g for debug build config, though.
    3) Sir nascardriver reply on one of my comments like "there is simplier alternatives to that script, like Cmake"; about *makefile* (which is "build configurations on command line"?) in 0.5: "However, because the makefiles are not part of the C++ core language, nor do you need to use them to proceed, we'll not discuss them as a part of this tutorial series.".

    P.S.: In 0.10, 0.11, and 0.12 there is "For GCC/G++ users".

    • nascardriver

      There is no -g flag in 0.7's "If you’re using g++ on the command line". Are you referring to something else?

      • Vitaliy Sh.

        Else, sir.
        0.7, 0.10, 0.11, 0.12 all have examples with a g++ on the c-line. That - 0.9 - is have none.

        Deletion (all g++ examples) *
        Addition (g++ -g there).

        * Because there is no simple way in spirit of that lessons to mimic the "Build Configurations" without the (C)Makefiles (0.5 - "we'll not discuss them").

        • nascardriver

          There are, and should be, examples about how to use g++ on the command line.
          There should be no examples about Makefiles.
          There is no example about g++ in this lesson, because there are no build-configurations in g++ (Only in build systems). -g is not a build configuration.

          • Vitaliy Sh.

            The g++ examples there is to show that it is exist to us? Chapter 3 is "g++"-less.

            • nascardriver

              The g++ examples are there so you can use g++.
              Chapter 3 is about debugging in an IDE. It's irrelevant which compiler the IDE is using.

              • Vitaliy Sh.

                "Yes, but we don’t recommend it for beginners.". And me anyway need to read about proper using it elsewhere, because search for "debug" on the main page shows only 3rd chapter. And any proper pupil expected to know how to debug? Thank you for all the reply, sir, but i've not get it in :) (yet?).

                Also, "debug" on the Site Index: 0.4, 0.9, 3.6, 7.12a: no "g++". That looks like a unneeded weight for people of my level, at least there.

                • nascardriver

                  Using a command-line compiler isn't recommended for beginners, but a lot of people want to use a command-line compiler. The g++ instructions aren't perfect, but it's better than not having them at all.
                  If you're not using a graphical debugger (In an IDE or editor), you should look into gdb (A command line debugger).

  • Vitaliy Sh.

    ... you’ll rarely have a reason to unless ...

    Possible typo: no comma before "unless".

  • oxygène

    Am I the only one using kdevelop for my first program? It's awesome though, don't forget to install cmake before creating your first project.

    • Teddy

      I started using kdevelop myself to compile some github projects. It has come a long way for sure. The ability to import CMake "project" to create a workspace is very slick. KDE has started porting some apps to Microsoft store so I assume KDevelop will make its way there eventually.

  • Dan Satt

    I'm using the new MSVS 2019 RC, and the default build config is debug x86.  I have the option to switch to x64, but I can't particularly think of why I would.  Any insight?

    • Hi Dan!

      Compiling in x86-64 (x64) allows the compiler to use instructions that are unavailable in IA-32 (x86), potentially speeding up your program.
      64bit allows you to access more memory than you could possibly have, while 32 bit is limited to around 4GB.
      IA-32 support is decreasing, you might find yourself wanting to use a library which is only available in x86-64.

  • Vinyamin

    Why do I not have the Build menu?

  • Mark

    Since you inserted a new lesson prior to this one (0.8—A few common C++ problems), the following sentence in the fifth paragraph needs to reflect that.

    “When the Hello World program from >>the previous lesson<< was built using Visual Studio, …”

    Should be corrected to read:

    “When the Hello World program from >>lesson 0.7<< was built using Visual Studio, …”

  • Ryan

    Hello! I believe I found a typo in the bottom section. Where you said 'In Code::Blocks, you should see aitem called Build Target', I think you meant to say 'an item' instead of 'aitem'.

  • Mark

    I can't find the Build target toolbar, because I am using codeblocks 17.12. Another question that is when and why do you need to use the highlight option? And last question is what are the "match case" and "use regex" options used for?

  • Willie

    Hello Alex.
    Is there a easy to read section where the variables are listed in a table form so the values can be seen and whatever else ....possibly how the variables are written?
    Trying to make it easy.

    • Alex

      I don't think I understand what you mean. Variables aren't mentioned in this lesson, so I'm not sure what problem you are trying to solve for.

  • Prynce

    Thanks so much I was able to write my first c++ program using Dev c++
    "Hello world!" Was displayed on my screen

  • Dear Sir!

    I am revising your lessons after completing the chapter 1 (including its sub-chapters).
    I have downloaded and installed Code Block-version 16.01 (Release 16.01 rev 10702 (2016-01-25 19:50:14) gcc 4.9.2 Windows/unicode - 32 bit).

    I failed to locate any 'Build target' there even after pasting my 'HellowWorld' program which otherwise runs perfectly.

    Can you please guide me in this respect?

    Thank you.

    Best regards.

    • Alex

      Did you set up both a release and debug release configuration when your project was created? Check out the screenshot here: -- it shows where you should be able to see your active build target on the interface (in this screenshot, the Debug configuration is selected)

  • Kushal Singh

    Hello Alex,

    When I navigate to Debug dir of my project folder , I find files with extensions: idb,pdb and pch. what are these files for and when are they generated ?


    • Alex

      .idb and .pdb are debug files produced by Visual Studio. .pch is a precompiled header file. These are all generated when you compile your program in debug configuration with precompiled headers enabled (which they are by default).

  • Kushal Singh

    How can I check the size of executable produced in debug/release configuration ?

    • Alex

      Use your OS file explorer/browser and find where your IDE put the executable for each of your configurations. This is most likely in a subfolder inside your project directory.

  • phong nguyen

    Hi, I just want to say thank you for the continuous efforts over the past couple of years. You rock!!!

  • Ahtazaz Khan

    Hi, i'm new here, i love your effort. i'm doing bachelor in Computer science. I have a little bit programming skills.But now i have a aim to learn Programming from the 0.I found your work best.Amazing tutorials.I have a question about building configurations.I have don't clear the build-configuration.Mean,What is the purpose of Build Configuration.How and when debug and release configurations use...?

    • Alex

      You'll generally use a debug configuration when developing your code or running it for your own purposes. This enables all debugging functionality, making it easier to find errors. If you decide to release your executable to others, you'll build it using a release configuration. This strips out all debugging information and uses more compiler optimizations, making your code smaller and faster.

      You can define custom release configurations as well, but there's no need unless you have special circumstances.

    • Tinsae Hunegnaw

      What Shall I doWhen I submit my assignment and project work for My instructor is that I have to use debug or release configuration of codes block...Window 10

      Thanks so much for Everything...Alex and all others

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