MPE/iX does not support the ACCEPT FROM INPUT STATUS statement due to limitations of the MPE/iX operating system. The lack of this functionality can cause problems for multi-threaded COBOL applications. If the application executes an ACCEPT in one thread, the runtime system is unable to task-switch to any other thread until the ACCEPT terminates.
A possible workaround for this limitation is to change the ACCEPT statement to use the BEFORE TIME clause. This causes the ACCEPT statement to time out which then allows the program to switch to another thread.