In
computer programming, a
runtime library is a set of low-level routines used by a
compiler to invoke some of the behaviors of a
runtime environment, by inserting calls to the runtime library into compiled executable binary. The runtime environment implements the execution model, built-in functions, and other fundamental behaviors of a
programming language. During execution (
run time) of that
computer program, execution of those calls to the runtime library cause communication between the executable binary and the runtime environment. A runtime library often includes built-in functions for memory management or
exception handling. Therefore, a runtime library is always specific to the platform and compiler.