1. code
Code written so that it can be shared by several programs or threads within a single process simultaneously. When code is reentrant, one thread can safely interrupt the execution of another thread, execute its own code, and then return control to the first thread in such a way that the first thread does not fail or behave in an unexpected way.
2. libary
Code written so that it can be shared by several programs or threads within a single process simultaneously. When code is reentrant, one thread can safely interrupt the execution of another thread, execute its own code, and then return control to the first thread in such a way that the first thread does not fail or behave in an unexpected way.