Simulink Real-Time C API

The Simulink® Real-Time™ C API consists of a series of C functions that you can call from a C or C++ custom program. This API is designed for multi-threaded operation on a 64-bit target computer.

The Simulink Real-Time C API DLL consists of C functions that you can incorporate into a custom program. You can use an application written through either interface to load, run, and monitor a real-time application without interacting with MATLAB®. Using the Simulink Real-Time C API, you write the custom program in a high-level language (such as C, C++, or Java®) that works with a real-time application. This option requires that you are an experienced programmer.

The xpcapi.dll file contains the Simulink Real-Time C API dynamic link library, which contains over 90 functions you can use to access the real-time application. Because xpcapi.dll is a dynamic link library, your program can use run-time linking rather than static linking at compile time. Use the Simulink Real-Time C API to build custom programs for development environments such as Microsoft® Foundation Class Library/Active Template Library (MFC/ATL) and third-party product APIs such as Altia®).

All custom Simulink Real-Time C API programs must link with the xpcapi.dll file ( Simulink Real-Time C API DLL). Also associated with the dynamic link library is the xpcinitfree.c file. This file contains functions that load and unload the Simulink Real-Time C API. Build this file along with the custom Simulink Real-Time C API program.

The Simulink Real-Time C API consists of blocking functions. A default timeout of 5 seconds controls how long a target computer can take to communicate with a development computer.

The documentation reflects the fact that the API is written in the C programming language. However, you can call the API functions from non-C languages, such as C++ and Java.


Refer to the compiler documentation of the non-C language for a description of how to access C functions from a library DLL. To access the Simulink Real-Time C API DLL, follow these directions. For information about working with 64-bit applications in Visual Studio, see 64-bit Applications (Microsoft docs).