User`s guide

cxxx Contents
Lock Presentation Space API—Function 60
This function allows the application to obtain or release exclusive control of the presentation space.
Prerequisite Functions
Connect Presentation Space (function 1).
WinHLLAPI(LOCKPSAPI,lpbyString,lpwLength,lpwReturnnCode)
Parameter Description
Data String
Locking parameters - a 3-byte string with the following
format:
Byte 1 Short name session ID, or space or null for
the current session.
Byte 2 One of the following:
u WHLL_LOCKAPI_LOCK to lock the
API.
u WHLL_LOCKAPI_UNLOCK to unlock
the API.
Byte 3 One of the following:
u
WHLL_LOCKAPI_RETURN to return if
the API is already locked.
u
WHLL_LOCKAPI_QUEUE to queue the
lock request if the API is already locked.
Data Length Must be specified (normally 3).
PS Position NA.
Code Description
WHLLOK The function was successful.
WHLLNOTCONNECTED
An invalid presentation space was specified, or was not
connected.
WHLLPARAMETERERROR An invalid option was specified.
WHLLSYSERROR The function failed due to a system error.
WHLLNOTSUPPORTED The function was not supported by the emulation
program.
WHLLPSENDED The session stopped.
WHLLLOCKERROR If _LOCK, the API was already locked.
If _UNLOCK, the API was not locked.
If the API is locked, the WinHLLAPI functions are rejected until the API is unlocked by using the
_UNLOCK option, or by disconnecting or resetting the presentation space.
Function Call
Call Parameters
Return Codes
Remarks