emRun++
The C++ runtime library for embedded applications

emRun++ implements classes and functions according to C++ standards. It also supplements the language features and incorporates the complete feature set of the C++17 standard defined by the International Organization for Standardization (ISO).

emRun++ provides all standard C++ header files together with wrappers for the C runtime library headers. The implementation includes mangled names of standard C functions, such as cos(float) and cos(double) to its C equivalents cosf() and cos().

Modern C++ applications rely on dynamic memory allocation. Objects are present in memory only while they are being used. Long-lived objects are usually created with “new” and destroyed with “delete”. While C++ takes care of calling objects’ constructors and destructors respectively, the regular C runtime library basically does the memory management.

emRun++ implements "new" and "delete" to use the alloc and free routines of the C runtime library emRun, which provides efficient use of heap memory, requiring the least overhead.

C++ defines the use of exceptions, in contrast to C where it is the user’s responsibility to manually recover from an error and pass errors up to all callers or to run into a fault. Exception handling offers a systematic and robust approach to cope with errors that cannot be recovered from locally. Exceptions can be thrown in case of an error and are passed up the call stack up to a point where they are caught and handled.

When an exception is thrown in a try block, all objects constructed within the block need to be destroyed, and the stack is unwound. To provide exception support, emRun++ implements the target architecture-dependent stack unwinding for all supported architectures.

C++ compilers define an application binary interface (ABI) which, for example, defines how objects are arranged, how name mangling works, or how virtual functions are implemented.

emRun++ implements the low-level functions of the C++ ABI to which the compiler implicitly adds calls in code generation. This enables the C++ library to be used out-of-the-box with any toolchain.