Character. SYS(1104) returns the number of bytes that could not be purged. SYS(1104) returns "0" if all memory is purged.

You can improve performance by calling SYS(1104) after executing commands that make extensive use of memory buffers. This function also clears internal buffers for open tables, forcing the tables to be refreshed, which is useful with large tables and in multiuser environments.

Note
The use of SYS(1104) will slow performance in applications that have a large number of buffered tables open.

Include the optional cAlias or nWorkArea parameter to purge the memory cache for a specific table or cursor. This can be useful in multiuser scenarios that use the INDEXSEEK( ) Function to search indexed tables.

Reference