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(A pre-compiled library would still give you the actual.h file for the #include statements, to satisfy declare-before-use in your own code). Rule of thumb: Only #include the header files, not the.cpp files! To build a simple project with multiple files in Visual C, first follow all of the usual directions for creating an empty. Walkthrough: Compile a C program on the command line.; 10 minutes to read +2; In this article. Visual C includes a C compiler that you can use to create everything from basic console programs to full Windows Desktop applications, mobile apps, and more.

Visual C++ includes a C compiler that you can use to create everything from basic console programs to full Windows Desktop applications, mobile apps, and more.

This walkthrough shows how to create a basic, 'Hello, World'-style C program by using a text editor, and then compile it on the command line. If you'd rather work in C++ on the command line, see Walkthrough: Compiling a Native C++ Program on the Command Line. If you'd like to try the Visual Studio IDE instead of using the command line, see Walkthrough: Working with Projects and Solutions (C++) or Using the Visual Studio IDE for C++ Desktop Development.

Prerequisites

C++ Compile Process

To complete this walkthrough, you must have installed either Visual Studio and the optional Visual C++ components, or the Build Tools for Visual Studio.

Visual Studio is a powerful integrated development environment that supports a full-featured editor, resource managers, debuggers, and compilers for many languages and platforms. For information on these features and how to download and install Visual Studio, including the free Visual Studio Community edition, see Install Visual Studio.

The Build Tools for Visual Studio version of Visual Studio installs only the command-line toolset, the compilers, tools, and libraries you need to build C and C++ programs. It's perfect for build labs or classroom exercises and installs relatively quickly. To install only the command-line toolset, download Build Tools for Visual Studio from the Visual Studio downloads page and run the installer. In the Visual Studio installer, select the C++ build tools workload, and choose Install.

Before you can build a C or C++ program on the command line, you must verify that the tools are installed, and that you can access them from the command line. Visual C++ has complex requirements for the command-line environment to find the tools, headers, and libraries it uses. You can't use Visual C++ in a plain command prompt window without some preparation. You need a developer command prompt window, which is a regular command prompt window that has all the required environment variables set. Fortunately, Visual C++ installs shortcuts for you to launch developer command prompts that have the environment set up for command line builds. Unfortunately, the names of the developer command prompt shortcuts and where they're located are different in almost every version of Visual C++ and on different versions of Windows. Your first walkthrough task is to find the right shortcut to use.

Note

A developer command prompt shortcut automatically sets the correct paths for the compiler and tools, and for any required headers and libraries. Some of these values are different for each build configuration. You must set these environment values yourself if you don't use one of the shortcuts. For more information, see Set the Path and Environment Variables for Command-Line Builds. Because the build environment is complex, we strongly recommend you use a developer command prompt shortcut instead of building your own.

These instructions vary depending on which version of Visual Studio you are using. To see the documentation for your preferred version of Visual Studio, use the Version selector control. It's found at the top of the table of contents on this page.

Open a developer command prompt in Visual Studio 2019

If you have installed Visual Studio 2019 on Windows 10, open the Start menu, and then scroll down and open the Visual Studio 2019 folder (not the Visual Studio 2019 app). Choose Developer Command Prompt for VS 2019 to open the command prompt window.

If you're using a different version of Windows, look in your Start menu or Start page for a Visual Studio tools folder that contains a developer command prompt shortcut. You can also use the Windows search function to search for 'developer command prompt' and choose one that matches your installed version of Visual Studio. Use the shortcut to open the command prompt window.

Open a developer command prompt in Visual Studio 2017

If you have installed Visual Studio 2017 on Windows 10, open the Start menu, and then scroll down and open the Visual Studio 2017 folder (not the Visual Studio 2017 app). Choose Developer Command Prompt for VS 2017 to open the command prompt window.

If you're running a different version of Windows, look in your Start menu or Start page for a Visual Studio tools folder that contains a developer command prompt shortcut. You can also use the Windows search function to search for 'developer command prompt' and choose one that matches your installed version of Visual Studio. Use the shortcut to open the command prompt window.

Open a developer command prompt in Visual Studio 2015

If you have installed Microsoft Visual C++ Build Tools 2015 on Windows 10, open the Start menu, and then scroll down and open the Visual C++ Build Tools folder. Choose Visual C++ 2015 x86 Native Tools Command Prompt to open the command prompt window.

If you're running a different version of Windows, look in your Start menu or Start page for a Visual Studio tools folder that contains a developer command prompt shortcut. You can also use the Windows search function to search for 'developer command prompt' and choose one that matches your installed version of Visual Studio. Use the shortcut to open the command prompt window.

Next, verify that the Visual C++ developer command prompt is set up correctly. In the command prompt window, enter cl and verify that the output looks something like this:

There may be differences in the current directory or version numbers, depending on the version of Visual C++ and any updates installed. If the above output is similar to what you see, then you're ready to build C or C++ programs at the command line.

C Files Endodontics

Note

If you get an error such as 'cl' is not recognized as an internal or external command, operable program or batch file,' error C1034, or error LNK1104 when you run the cl command, then either you are not using a developer command prompt, or something is wrong with your installation of Visual C++. You must fix this issue before you can continue.

If you can't find the developer command prompt shortcut, or if you get an error message when you enter cl, then your Visual C++ installation may have a problem. If you're using Visual Studio 2017 or later, try reinstalling the Desktop development with C++ workload in the Visual Studio installer. For details, see Install C++ support in Visual Studio. Or, reinstall the Build Tools from the Visual Studio downloads page. Don't go on to the next section until this works. For more information about installing and troubleshooting Visual Studio, see Install Visual Studio.

How To Compile C++ In Terminal

Note

Depending on the version of Windows on the computer and the system security configuration, you might have to right-click to open the shortcut menu for the developer command prompt shortcut and then choose Run as Administrator to successfully build and run the program that you create by following this walkthrough.

Create a C source file and compile it on the command line

1. In the developer command prompt window, enter cd c: to change the current working directory to the root of your C: drive. Next, enter md c:simple to create a directory, and then enter cd c:simple to change to that directory. This directory will hold your source file and the compiled program.

2. Enter notepad simple.c at the developer command prompt. In the Notepad alert dialog that pops up, choose Yes to create a new simple.c file in your working directory.

3. In Notepad, enter the following lines of code:

4. On the Notepad menu bar, choose File > Save to save simple.c in your working directory.

5. Switch back to the developer command prompt window. Enter dir at the command prompt to list the contents of the c:simple directory. You should see the source file simple.c in the directory listing, which looks something like:

   The dates and other details will differ on your computer. If you don't see your source code file, simple.c, make sure you've changed to the c:simple directory you created, and in Notepad, make sure that you saved your source file in this directory. Also make sure that you saved the source code with a .c file name extension, not a .txt extension.

6. To compile your program, enter cl simple.c at the developer command prompt.

   You can see the executable program name, simple.exe, in the lines of output information that the compiler displays:

   Note

   If you get an error such as 'cl' is not recognized as an internal or external command, operable program or batch file,' error C1034, or error LNK1104, your developer command prompt is not set up correctly. For information on how to fix this issue, go back to the Open a developer command prompt section.

   Note

   If you get a different compiler or linker error or warning, review your source code to correct any errors, then save it and run the compiler again. For information about specific errors, use the search box at the top of this page to look for the error number.

7. To run your program, enter simple at the command prompt.

   The program displays this text and then exits:

   Congratulations, you've compiled and run a C program by using the command line.

Next steps

This 'Hello, World' example is about as simple as a C program can get. Real world programs have header files and more source files, link in libraries, and do useful work.

You can use the steps in this walkthrough to build your own C code instead of typing the sample code shown. You can also build many C code sample programs that you find elsewhere. To compile a program that has additional source code files, enter them all on the command line, like:

cl file1.c file2.c file3.c

The compiler outputs a program called file1.exe. To change the name to program1.exe, add an /out linker option:

cl file1.c file2.c file3.c /link /out:program1.exe

And to catch more programming mistakes automatically, we recommend you compile by using either the /W3 or /W4 warning level option:

cl /W4 file1.c file2.c file3.c /link /out:program1.exe

The compiler, cl.exe, has many more options you can apply to build, optimize, debug, and analyze your code. For a quick list, enter cl /? at the developer command prompt. You can also compile and link separately and apply linker options in more complex build scenarios. For more information on compiler and linker options and usage, see C/C++ Building Reference.

You can use NMAKE and makefiles, or MSBuild and project files to configure and build more complex projects on the command line. For more information on using these tools, see NMAKE Reference and MSBuild.

The C and C++ languages are similar, but not the same. The Microsoft C/C++ compiler (MSVC) uses a simple rule to determine which language to use when it compiles your code. By default, the MSVC compiler treats all files that end in .c as C source code, and all files that end in .cpp as C++ source code. To force the compiler to treat all files as C non-dependent of file name extension, use the /Tc compiler option.

MSVC is compatible with the ISO C99 standard, but not strictly compliant. In most cases, portable C code will compile and run as expected. Visual C++ doesn't support most of the changes in ISO C11. Certain library functions and POSIX function names are deprecated by MSVC. The functions are supported, but the preferred names have changed. For more information, see Security Features in the CRT and Compiler Warning (level 3) C4996.

See also

Walkthrough: Creating a Standard C++ Program (C++)
C Language Reference
Projects and build systems
Compatibility

The most basic multi-module monster project in C programming has two source code files. Each file is separate — written, saved, and compiled individually — but eventually brought together as one unit by the linker. The linker, which is part of the build process in Code::Blocks, is what creates a single program from several different modules.

What’s a module?

A module is a source code file and its compiled object file. Together, the source code and object files are a module. Then the various object files are linked to build a program. The entire operation starts with separate source code files.

THE MAIN.C SOURCE CODE FILE

Exercise 1: Fire up a new project in Code::Blocks named ex2401. Create the project as you normally would: Type the source code from The main.c Source Code File into the editor as the contents of the main.c file. Save the file.

C++ Multiple Source Files

Don’t build yet! After all, the code references the second() function, which doesn’t seem to exist anywhere. It’s prototyped, as is required for any function that’s used in your code, but the second() function is found in another module. To create that module in Code::Blocks, follow these steps:

1. Save the current project, ex2401.

2. Choose File→New→Empty File.

3. Click the Yes button when you’re prompted to add the file to the active project.

   The Save File dialog box appears.

4. Type alpha.c as the filename and then click the Save button.

   The new file is listed on the left side of the Code::Blocks window, beneath the Sources heading where the main.c file is listed. A new tab appears in the editor window, with the alpha.c file ready for editing.

5. Click the alpha.c tab to begin editing that file.

6. Type the source code from The alpha.c Source Code File into the alpha.c file in Code::Blocks.

7. Save the ex2401 project.

8. Build and run.

THE ALPHA.C SOURCE CODE FILE

G++ Compile Header Files

Here’s the output you should see in the test window on your computer:

The two source code files aren’t “glued together” by the compiler; each source code file is compiled individually. A separate object code file is created for each one: main.o and alpha.o. It’s these two object code files that are then linked together, combined with the C standard library, to form the final program.

• The main module for a multi-module C program is traditionally named main.c. That’s probably why Code::Blocks names the first (and, often, only) project source code file main.c.

• Only source code files contained within the same project — found beneath the Sources branch — are linked together.

• To compile and link source code files in a terminal window, use the following command:

  This command compiles the source code files main.c and alpha.c, links together their object files, and then creates as output (-o) the program file ex2401.