Windows Store Apps, the Windows Runtime, and the C Run-Time
For the latest documentation on Visual Studio 2017 RC, see Visual Studio 2017 RC Documentation.
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
spawnfamilies 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.
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
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.