C Runtime Library-Supported API Overview

Microsoft provides a supported version of its C Runtime libraries with every version of Visual Studio and, to be as seamless as possible with Microsoft, RTX provides support for a number of versions of the Microsoft Visual Studio C Runtime libraries. By providing this C Runtime support, we allow for the same code to be built as either a Windows or an RTSS process, with little or no behavioral differences. RTX makes no functionality or logic modifications to the C Runtime library unless absolutely necessary. This helps to keep API behavior between Windows and RTSS applications as close as possible.

As a result, when upgrading the Visual Studio build environment for an RTSS application that uses C Runtime, you must also upgrade the C Runtime version to the supported version for that Visual Studio. Additionally, you should make sure that any calls to the C Runtime still behave as expected and provide the determinism you require for your application.

RTX supports the C Runtime libraries listed in the sections below. See the C Runtime API Reference for more details about the specific library calls that are supported.

NOTE: Depending on the version of Visual Studio you use, floating-point settings can have an impact on API performance. The MSDN article "Microsoft Visual C++ Floating-point Optimization" explains the compiler flags available.