Portability Subroutine: Flushes the contents of an external unit buffer into its associated file.
CALL FLUSH (lunit)
(Input) INTEGER(4). Number of the external unit to be flushed. Must be currently connected to a file when the subroutine is called. This routine is thread-safe, and locks the associated stream before I/O is performed.
The flush is performed in a non-blocking mode. In this mode, the command may return before the physical write is completed. If you want to use a blocking mode of FLUSH use COMMITQQ.