In
computing, a
computer program or
subroutine is called
reentrant if it can be interrupted in the middle of its execution and then safely called again ("re-entered") before its previous invocations complete execution. The interruption could be caused by an internal action such as a jump or call, or by an external action such as a
hardware interrupt or
signal. Once the reentered invocation completes, the previous invocations will resume correct execution.