As in VFP8 Help:

SYS(1104) - Purge Memory Cache

Purges memory cached by programs and data, and clears and refreshes buffers for open tables.

SYS(1104)Returns
Numeric. 0, if successful

Remarks
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.

>Thanks Yuri -
>
>My help didn't list sys(1104)- must be a undocumented command where can I get details?