Windows Store Apps, the Windows Runtime, and the C Run-Time

 

For the latest documentation on Visual Studio 2017, see Visual Studio 2017 Documentation.

For the latest documentation on Visual Studio 2017, see Windows Store Apps, the Windows Runtime, and the C Run-Time on docs.microsoft.com. Windows 8.x Store apps are programs that run in the Windows Runtime that executes on Windows 8. The Windows Runtime is a trustworthy environment that controls the functions, variables, and resources that are available to a Windows 8.x Store app. However, by design, Windows Runtime restrictions prevent the use of most C Run-Time Library (CRT) features in Windows 8.x Store apps.

The Windows Runtime does not support the following CRT features:

  • Most CRT functions that are related to unsupported functionality.

    For example, a Windows 8.x Store app cannot create a process by using the exec and spawn families of routines.

    When a CRT function is not supported in a Windows 8.x Store app, that fact is noted in its reference article.

  • Most multibyte character and string functions.

    However, both Unicode and ANSI text are supported.

  • Console apps and command-line arguments.

    However, traditional desktop apps still support the console and command-line arguments.

  • Environment variables.

  • The concept of a current working directory.

  • Windows 8.x Store apps and DLLs that are statically linked to the CRT and built by using the /MT or /MTd compiler options.

    That is, an app that uses a multithread, static version of the CRT.

  • An app that's built by using the /MDd compiler option.

    That is, a debug, multithread, and DLL-specific version of the CRT. Such an app is not supported on the Windows Store.

For a complete list of CRT functions that are not available in a Windows 8.x Store app and suggestions for alternative functions, see CRT functions not supported with /ZW.

Compatibility
Windows Runtime Unsupported CRT Functions
Run-Time Routines by Category

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