If you specify this directive the run-time system determines whether the program is active in a thread and prevents any other thread entering the active program. This directive should be used on the first COBOL program to be executed on any given thread.
Note that the code to determine this takes time and is called on every program entry. Programs should be compiled with this directive only if they are going to run in a multi-threaded environment.
Comments:
If you specify this directive the run-time system determines whether the program is active in a thread and prevents any other thread entering the active program. This directive should be used on the first COBOL program to be executed on any given thread.
Note that the code to determine this takes time and is called on every program entry. Programs should be compiled with this directive only if they are going to run in a multi-threaded environment.