Note: This API calls are shared between DOS and Win16 personality.
DOSSHELL is a stripped down version of 16-bit Windows. Some APIs shared and same. DOSSHELL uses older version of API, but Win16 has more advanced APIs.
Int 2FH, AX=4A05H, SI=02H
Switch to next task in Z order list
CF is reset - ok CF is set - error. Only one task in list
Function switches Z order list so next task in z-list become first, first become second and so on.