NAME
LockIBase -- Invoke semaphore arbitration of IntuitionBase.
SYNOPSIS
Lock = LockIBase( LockNumber )
D0 D0
ULONG LockIBase( ULONG );FUNCTION
Grabs Intuition internal semaphore so that caller may examine IntuitionBase safely. This function is not a magic "fix all my race conditions" panacea.
The idea here is that you can get the locks Intuition needs before such IntuitionBase fields as ActiveWindow and FirstScreen are changed, or linked lists of windows and screens are changed.
Do Not Get Tricky with this entry point, and do not hold these locks for long, as all Intuition input processing will wait for you to surrender the lock by a call to UnlockIBase.
NOTE WELL: A call to this function MUST be paired with a subsequent call to UnlockIBase, and soon, please.
NOTE WELL: Do not call any Intuition functions (nor any graphics, layers, dos, or other high-level system function) while holding this lock.
INPUTS
A long unsigned integer, LockNumber, specifies which of Intuition's internal locks you want to get. This parameter should be zero for all forseeable uses of this function, which will let you examine active fields and linked lists of screens and windows with safety.
RESULT Returns another ULONG which should be passed to UnlockIBase to surrender the lock gotten by this call.
BUGS This function must not be called while holding any other system locks such as layer or LayerInfo locks.
SEE ALSO
UnlockIBase, layers.library/LockLayerInfo, exec.library/ObtainSemaphore