* SETMEM(0) returns the total number of bytes currently in the far heap memory area.
* The byte size indicates the number of bytes to increase or decrease the far heap.
:* If the byte size is negative, SETMEM decreases the far heap by the indicated number of bytes.
:* If the byte size is positive, SETMEM '''attempts''' to increase the far heap space by the number of bytes.
* If SETMEM cannot change the far heap by the requested number of bytes, it reallocates as many bytes as possible.
* SETMEM can be used in mixed-language programming to decrease the far heap space so procedures in other languages can dynamically allocate far memory.
:'''Note: A first call to SETMEM trying to increase the far heap has no effect because Basic'''
::'''allocates as much memory as possible to the far heap when a program starts.'''