# Platform and Operating Systems (OS)

EC-Simulator and the EcSimulatorHilDemo example application support a wide range of operating systems and platforms.
This chapter covers OS-specific setup, build, and compiler settings for each supported platform.

EC-Simulator is implemented in portable C++ and contains no direct operating system call. Everything it requires from its environment, such as memory, threads, synchronization and time, is obtained through a small OS layer. Only this layer is platform dependent, all other sources are built unmodified on every supported platform.

The OS layer interface is declared in the header file `EcOs.h` and covers the following services:

Memory
: Allocation as well as memory and string operations.

Threads
: Thread creation including priority and CPU affinity.

Synchronization
: Locks of several types and events.

Time
: Millisecond tick, sleep, host system time and high resolution counter.

Module loading
: Binding of the [Real-time Ethernet Driver](emll.html.md#real-time-ethernet-driver) at runtime on platforms supporting dynamically loaded modules.

Debug
: Assertions and string formatting.

The platform specific implementation consists of `EcOsPlatform.h` and `EcOs.cpp`. Most functions are that easy that they can be implemented using simple C macros mapping to the native API.

The OS layer is initialized with `EC_T_OS_PARMS`, either by calling `OsInit()` as done by the demo applications, or by [`EC_T_SIMULATOR_INIT_PARMS::pOsParms`](api_general.html.md#_CPPv4N25EC_T_SIMULATOR_INIT_PARMS8pOsParmsE) when calling [`esInitSimulator()`](api_general.html.md#_CPPv415esInitSimulator10EC_T_DWORDPK25EC_T_SIMULATOR_INIT_PARMS).

#### NOTE
Real-time behaviour is determined by the operating system and not by EC-Simulator.