What is reentrant tasks and functions

Tasks and functions without optional keyword automatic are static , with all declared items being statically allocated. These items will be shared across all uses of the task and functions executing simultaneously.  Task  and  functions  with  optional  keyword  automatic  are  automatic  tasks  and functions. All items declared inside automatic tasks and functions are allocated dynamically for every invocation. Automatic task items and function items can't be accessed by hierarchical references.