The Microsoft run-time library supports American National Standards Institute (ANSI) C and UNIX C. In this documentation, references to UNIX include XENIX, other UNIX-like systems, and the POSIX subsystem in Windows 2000, Windows XP, Windows Server 2003, and Windows Vista. The description of each run-time library routine includes a compatibility section for the following targets.
- ANSI 
- ISO C 95 
- Windows 2000 
- Windows XP 
- Windows Server 2003 
- Windows Vista 
All run-time library routines included with this product are compatible with the Windows API.