OS_Poll, poll for an application

RST 20H, DEFW $FC06

IN:

     IX = 0, fetch first application in the machine
     IX <> 0 (current application handle), fetch next application

     Fc = 0
     IX = new application handle

     Fc = 1
          A = RC_EOF, no more applications available (IX now invalid)

     ..BCDEHL/..IY same
     AF....../IX.. different

Internal operating system usage.
An invalid input application handle also results in RC_EOF.

     -

OS_Ent, enter an application
DC_Nam, Name current application
DC_Ent, enter new application
DC_Pol, poll for card usage
OS_Stk, stack the current process (application)
OS_Exit, exit an application
DC_Bye, exiting current application
OS_Bye, exit application
OS_Use, process card usage