IN: BC = timeout in centiseconds (-1, no timeout)
OUT: Fc = 0, success and A = key code
Fc = 1, failure and A = RC_TIME, timeout elapsed
Registers changed after return:
Internal operating system usage only.
This call returns the key code corresponding to a keyboard input. Qualifiers (SHIFT, DIAMOND and SQUARE) and foreign keyboard mappings are implemented. The operating system MTH is bypassed. Thus the menu commands, the application swapping are inactive. This call should not be used at application level.
Conversion of key code to ISO character is performed by OS_Iso API.
GN_Sip, system input line routine
OS_In, read (wait for) character from standard input
OS_Pur, purge keyboard buffer
OS_Tin, read character from standard input, with timeout
OS_Xin, examine input