CLion 2018.2 Help

Quick Start Guide

This Quick Start Guide is designed to introduce the key concepts and help you make a quick start with the IDE.

Step 0. Before you start

What languages does CLion Support?

With CLion you can develop applications in C and C++. In addition, it fully supports Objective-C/C++, HTML (including HTML5), CSS, JavaScript, and XML: these languages are bundled in the IDE via plugins and are switched on for you by default. See CLion Features in Different Languages for more details.

Support for other languages can also be added via plugins (go to Settings | Appearance and Behavior | Plugins (or CLion | Preferences | Appearance and Behavior | Plugins for macOS users) to find out more or set them up during the first IDE launch).

What platforms can I run CLion on?

CLion is a cross-platform IDE that works on Windows, macOS, and Linux.

Which compilers are supported by the IDE?

CLion supports GCC, Clang and Microsoft Visual C++ compilers. This means that on Windows you can select between MinGW (or MinGW-w64), Cygwin and Microsoft Visual Studio tool sets.

What do I need to start with CLion? What are the system requirements?

In general to develop in C/C++ with CLion you need:

  • GCC/G++ or Clang, which in case of Windows means using toolchains: MinGW (or MinGW-w64), Cygwin 2.8 (minimum required), or Visual Studio if you are going to use Microsoft Visual C++ compiler instead of GCC/C++ or Clang (refer to our tutorial).

CLion includes bundled GDB (for MinGW on Windows), recent version of LLDB (on Linux and macOS), JDK 1.8 and CMake so you don’t need to install them separately. Check the bundled CMake version number in File | Settings |Build, Execution, Deployment | Toolchains (or CLion | Preferences |Build, Execution, Deployment | Toolchains if you are macOS user).

You can install any of that packages on your system, including custom versions of CMake, compilers and GDB.

The system requirements are:

  • Windows 7.0 or later (64 bit only)

  • Cygwin x64 with installed packages: gcc/g++, cmake, make, gdb
    MinGW with installed packages: gcc/g++ and make
    Windows Subsystem for Linux (WSL)
    Visual Studio 2013, 2015 or 2017 with C++ support.

  • macOS 10.9.4+

  • Xcode must be installed with the command line tools

  • After Xcode installation or update, make sure you've executed xcode-select --install command in the terminal

  • Linux 64 bit

  • GCC/G++ or Clang

Please find more details about the requirements for CLion here.

What project formats are supported?

Everything you do in CLion is done within the context of a project. It serves as a basis for coding assistance, bulk refactoring, coding style consistency, etc.

CLion supports CMake, Gradle, and compilation database projects. CMake support is the most comprehensive: it includes creating, opening, building, running and debugging a project. For Gradle, you can open and run applications, and compilation database projects can be opened and managed as well.

Step 1. Open/Create a project in CLion

You have three options to start working on a project inside the IDE:

Open an existing project

Begin by opening one of your existing projects stored on your computer. If your project uses the CMake build system, you can do the following from the Welcome screen (or File menu in the IDE): click New Project and locate the CMakeLists.txt file:

Welcome Screen
If your project has already been generated, locate the directory with generated CMake files and open it as project in CLion, or point to CMakeCache.txt file. Otherwise select Import Project from Sources and specify the location of the sources, then select project files and include directories:
Import CMake project
CLion will then create a CMake project from your sources for you.

To open a Gradle or compilation database project, choose the build.gradle or compile_commands.json file, and select Open as Project.

Check out an existing project from Version Control

You can also download sources from a VCS storage or repository. Choose Git, GitHub, CVS, Mercurial, Subversion, Perforce or TFS, and then enter your credentials to access the storage. Then, enter a path to the sources and clone the repository to the local host:

cl QST cloneRepGithub

Create a project from scratch

If you prefer to start from scratch, click New Project on the Welcome screen, enter your project’s name in the dialog, and a sample project will be created:

Creating a project form scratch

Step 2. Look around

When you launch CLion for the very first time, or when there are no open projects, you see the Welcome screen. It gives you the main entry points into the IDE: creating or opening a project, checking out a project from version control, viewing documentation, and configuring the IDE. When a project is opened, you see the main window divided into several logical areas. Let’s take a moment to see the key UI elements here:

Look around
  1. Project view on the left side displays your project files.

  2. Editor on the right side, where you actually write your code. It has tabs for easy navigation between open files

  3. Navigation bar above the editor additionally allows you to quickly run and debug your application as well as do basic VCS actions.

  4. Left gutter, the vertical stripe next to the editor, shows the breakpoints you have, and provides a convenient way to navigate through the code hierarchy like going to definition/declaration. It also shows line numbers and per-line VCS history.

  5. Right gutter, on the right side of the editor. CLion constantly monitors the quality of your code and always shows the results of its code analysis in the right gutter: errors, warnings, etc. The square in the top right-hand corner shows the overall status of code analysis for the whole file.

  6. Tool windows are specialized windows attached to the bottom and sides of the workspace and provide access to typical tasks such as project management, source code search and navigation, CMake information, integration with version control systems, etc.

  7. The status bar indicates the status of your project and the entire IDE, and shows various warnings and information messages like file encoding, line separator, inspection profile, etc. In addition, here you can find the Resolve Context chooser for switching between contexts (with or without debug info) to resolve your code in the IDE with the desired definitions.

Step 3. Customize your environment

Feel free to tweak the IDE so it suits your needs perfectly and is as helpful and comfortable as it can be. Go to File | Settings (CLion | Preferences for macOS users) to see the list of available customization options.


The first thing to fine-tune is the general "look and feel." Go to File | Settings | Appearance and Behavior | Appearance (CLion | Preferences | Appearance and Behavior | Appearance for macOS users) to select the IDE theme: the default light theme, or Darcula if you prefer a darker setting.


The many pages available under File | Settings | Editor (CLion | Preferences | Editor for macOS users) help you adjust every aspect of the editor’s behavior. A lot of options are available here, from general settings (like Drag'n'Drop enabling, scrolling configuration, etc.), to color configuration for each available language and use case, to tabs and code folding settings, to code completion behavior and even postfix templates.

Code style

Code style can be defined for each language under File | Settings | Editor | Code Style (CLion | Preferences | Editor | Code Style for macOS users). You can also create and save your own coding style scheme.

cl QST codeStyleSettings


CLion uses the keyboard-centric approach, meaning that nearly all actions possible in the IDE are mapped to keyboard shortcuts. The set of keyboard shortcuts you work with is one of your most intimate habits — your fingers "remember" certain combinations of keys, and changing this habit is easier said than done. CLion supplies you with a great default keymap (choose Help | Default Keymap Reference on the main menu) making your coding really productive and convenient. However, you can always change it by going to File | Settings | Appearance and Behavior | Keymap (CLion | Preferences | Appearance and Behavior | Keymap for macOS users). There are also some pre-defined keymaps (like Emacs, Visual Studio, Eclipse, NetBeans, or Xcode), and you can also create your own keymap based on an existing one.

If you feel most productive with vi/Vim, an emulation mode will give you the best of both worlds. Simply enable the IdeaVim plugin in the IDE and select the vim keymap.

Step 4. Code with smart assistance

CLion takes care of the routine so that you can focus on the important. Use the following coding capabilities to create error-free applications without wasting precious time.

Code completion

Code completion is a great time-saver, regardless of the type of file you’re working with. There are two types of code completion in CLion: basic (Ctrl+Space) and smart(Ctrl+Shift+Space). Basic completion works as you type and completes any name instantly. Smart completion analyzes the context you’re currently working in and offers more accurate suggestions based on that analysis. It filters the list of functions and variables to match the expression type:

cl QST smartCodeCompletion

Intention actions

CLion keeps an eye on what you are currently doing and makes smart suggestions, called intention actions, to save more of your time. Indicated with a lightbulb, intention actions let you apply automatic changes to code that is correct (in contrast to code inspections that provides quick-fixes for code that may be incorrect). Did you forget to add some parameters and field initializers to the constructor? Not a problem with CLion. Click the lightbulb (or press Alt+Enter) and select one of the suggested options:

cl QST intentionAction
The full list of available intention actions can be found in File Settings | Editor | Intentions or CLion | Preferences | Editor | Intentions for macOS users.

Step 5. Keep your code neat

CLion monitors your code and tries to keep it accurate and clean. It detects potential errors and problems and suggests quick-fixes for them.

Every time the IDE finds unused code, an endless loop, hidden upper scope, '=' in a conditional expression, and many other things that likely require your attention, you’ll see a lightbulb. Click it, or press Alt+Enter, to apply a fix:

cl QST inspection
The complete list of available inspections can be found under Settings | Editor | Inspections (or CLion | Preferences | Editor | Inspections for macOS users). You can disable some of them, or enable others, plus you can adjust the severity of each inspection. You decide whether it should be considered an error or just a warning.

Step 6. Generate some code

Writing code can be a lot easier and quicker when you use the code generation options available in CLion. The Code | Generate menu (Alt+Insert) will help you with constructor/destructor or getter/setter generation, as well as suggest overriding/implementing some functions (Ctrl+O/Ctrl+I:

cl QST impl over
Use live templates (choose Code | Insert Live Template or press Ctrl+J) to produce entire code constructs. You can explore the available ready-to-use live templates in the Settings dialog (Settings | Editor | Live templates or CLion | Preferences | Editor | Live Templates if you are macOS user). If you see that you are lacking something especially important for your development, extend this set of templates with your own.

Also, consider quickly surrounding your code with complete constructs (choose Code | Surround With or press Ctrl+Alt+T. For example, select an if statement:

cl QST surround with 1
and you will get:
cl QST surround with 2

Step 7. Find your way through

When your project is big, or when you have to work with someone else’s code, it’s vital to be able to quickly find what you are looking for and dig into the code. This is why CLion comes with a set of navigation features that will help you find your way through any code no matter how tangled it is.

Basic search

To find where a particular symbol is used, CLion suggests full-scale search via Find Usages (Alt+F7):

Find usages
You also have the option to search only in the current file (Ctrl+F), or within a directory, any arbitrary scope, or the entire project (Ctrl+Shift+F).

Project navigation

You can tell a lot just looking at your File Structure, with its imports or call hierarchies, and possibly use it to navigate to:

The icons in the left-hand gutter can also help you with navigation:
cl QST goToSubclass

Navigate through the timeline

Remembering all your activity in the project, CLion can easily navigate you to the Recent Files (Ctrl+E) or Recently Changed Files (Shift+Alt+C). To go through the history of changes, try using Back/Forward navigation (Ctrl+Alt+Left/Ctrl+Alt+Right) and/or go to last edit location (Ctrl+Shift+Backspace).

Find Action

Take advantage of many smart actions possible with CLion. For example, use the Find Action search (Ctrl+Shift+A): just type a part of the action name, and the IDE will show you the list of all available options. Then, select the action you need:

cl QST findAction

Search Everywhere

If you have a general idea of what you're looking for, you can always locate the corresponding element using one of the existing navigation features. But what if you really want to look for something in every nook and cranny? The answer is to use Search Everywhere! To try it, click the magnifying glass in the upper right-hand corner of the window, or invoke it with Double Shift (press Shift twice).

Step 8. Configure the CMake build system

For CMake projects, CLion takes all the information about the project from CMakeLists.txt files: the source and header files included, the defines, options, etc. Every change you make in CMakeLists.txt is handled automatically by CLion, but you can also call the Update CMake Project action manually from the CMake tool window.

Note that when you build an application, CLion calls the CMake command, so you don't need to take care of this step separately.

Step 9. Run and debug

Run configuration

Now when you’ve played with the code and discovered what you can do with it, it’s time to run your app. In CLion you do this via the Run/Debug Configurations. Open Run | Edit Configurations to see all the available options. For example, if you want to run some script before/after the build phase, you can do this easily by creating an external tool:

Run/Debug Configuration
To run a configuration, press Shift+F10.


Does your application stumble on a run-time error? To find out what’s causing it, you will have to do some debugging.

CLion includes bundled GDB for macOS, Linux, and Windows (in case of MinGW only), as well as bundled LLDB for macOS and Linux. Also, you can use custom GDB on all the platforms.

Debugging starts with placing breakpoints at which program execution will be suspended, so you can explore program data. Just click the left gutter of the line where you want the breakpoint to appear. To start debugging your application, press Shift+F9. Then go through the program execution step by step (see the available options in Run menu or in Debug tool window), evaluate any arbitrary expression, add watches and manually set values for the variables:


Step 10. Keep your source code under Version Control


If you are keeping your source code under version control, you will be glad to know that CLion integrates with many popular version control systems: Git (or GitHub), Mercurial, Perforce, TFS, Subversion and CVS. To specify credentials and any settings specific to a particular VCS, go to Settings | Current Project | Version Control> (or CLion | Preferences | Current Project | Version Control if you are macOS user).

The VCS menu will give you a clue about what commands are available. For example, you can see the changes you’ve made, commit them, create changelists and much more from the Changes view: VCS | Show Changes View (or just press Alt+9). Also some basic commands can be easily found in the Navigation bar above the editor:

cl QST VCSbasic

Local history

In addition to traditional version control, you can use the local history. With Local History, CLion automatically tracks changes you make to the source code, the results of refactoring, etc. Local history is always enabled. To view it for a file or a folder, bring up Local History by selecting VCS | Local History | Show History. Here you can review the changes, revert them or create a patch.

Step 11. That’s it! Go ahead and develop with pleasure!

We hope this brief overview of essential CLion features will give you a quick start. There are many important features that make a developer’s life easier and more fun, and their source code neater and cleaner. Take these first few steps now, and then dig deeper when you feel the time is right. Enjoy CLion!

With any questions please visit our CLion Discussion Forum, twitter and blog, where you can find news, updates, and useful tips and tricks. Also, don't hesitate to report any problems to our support team) or the CLion issue tracker.

Last modified: 27 November 2018

See Also