\ File:         com_ports.spf
\ Date:         28.06.2004
\ Author:       Nicholas Nemtsev, Valery Kondakoff
\ Description:  Tests the specified COM-port and returns TRUE (-1) if
\               the port is free (not used by some devices or 
\               applications) or returns FALSE (0) if the port 
\               is busy (used by some devices or applications)

\ New words:    S" com_port_name" IsComPortFree?

0 [IF]   \ this is a comment string

Examples:

#( test_com_port 
NoActive
Action:
    S" COM2" IsComPortFree?
    IF
        MSG: "free"
    ELSE
        MSG: "busy"
    THEN
)#

#( test_com_port1
NoActive
Rule: S" COM1" IsComPortFree?
Action:
    MSG: "free"
)#

[THEN]   \ this is a comment string


: IsComPortFree? ( a u -- ? )
    R/O OPEN-FILE DROP
    DUP INVALID_HANDLE_VALUE = 0=
    IF
        CloseHandle DROP TRUE  
    ELSE
        DROP FALSE
    THEN
;