Sys
    ------------------
    Basic keyword
     
     
    Use: The SYS statement calls one of the SWI routines in the
    operating system, or in a extension module. The first expr is
    either the SWI number or the SWI name. If it is a name, this
    must first be looked up, and this takes some time.
     
    Syntax is: Sys "SomeSwi",expr% To expr2%;expr3%
     
    Example:
    Sys "OS_WriteC",7
    Rem This sounds the bell.
     
    Sys 6,161,5 To ,,fs%
    Rem Read the default filing system number from CMOS RAM.
     
    The number and variety of available SYS calls is vast. You will
    need to read the documentation for the particular call to find out
    what the parameters and return values are.
     
    One other useful facility is the ability to read the processor flags
    on return.
     
    Sys "XOS_CLI","Fred" To ;flags%
     
    If bit 0 of returned value is 1, an error occurred and you can
    take appropriate action.