@SMPOKE[handle,offset,size,value] : Write a value to shared memory
handle - a handle from @SMOPEN
offset - the byte offset in the buffer (decimal or hex)
size - the size of the value (in bytes):
1 - character
2 - short
4 - int
8 - int64
value - the value to poke
@SMPOKE returns 0 on success.