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action:Semaphore_Lock
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action:Semaphore_Lock [2019/08/24 20:43] JMichaelTX [Preventing Multiple Executions of One or More Macros] |
action:Semaphore_Lock [2019/08/25 20:43] JMichaelTX Rev #2 |
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| Occasionally there are cases where multiple macros can be triggered, or the same macro triggered again, before the other macros complete. This can sometimes cause a problem, which needs to be prevented. | Occasionally there are cases where multiple macros can be triggered, or the same macro triggered again, before the other macros complete. This can sometimes cause a problem, which needs to be prevented. | ||
| - | **The primary purpose of using a //Semaphore Lock// is to prevent simultaneous macro executions of the same, or related, macros.**\\ | + | **The //Semaphore actions// require a _Semaphore Name_, which uniquely identify each _Semaphore Lock_.** Use a different _Semaphore Name_ to identify different (independent) _Semaphore Locks_. |
| - | In order to achieve this: | + | |
| + | **In order to prevent simultaneous executions (instances) of one or more macros that have _Semaphore Locks_ with the same _Semaphore Name_, do the following:**\\ | ||
| * Place a //Semaphore Lock// Action (using the same Semaphore Name) as the first action of each Macro that you wish to prevent executing simultaneously. | * Place a //Semaphore Lock// Action (using the same Semaphore Name) as the first action of each Macro that you wish to prevent executing simultaneously. | ||
| - | * The lock will remain in place preventing any other macros that try to execute until the first macro completes, or until you execute a Semaphore Unlock action. | + | * The lock will remain in place, preventing the other macros from executing, until the current macro instance (("macro instances" refers to both additional instances of the same macro _and_ instances of other macros that use the same named Semaphore Lock Action.)) completes or until the semaphore is unlocked with a Semaphore Unlock action. |
| - | * You can also cause all additional macro instances to be immediately cancelled by setting a very short timeout (1 hundredth of a second) for the Semaphore Action. | + | * When the Semaphore is _unlocked_ the next macro instance in the queue will execute in First In First Out (FIFO) order. Since the first Action is a _Semaphore Lock_, only one macro instance is executed at a time. |
| + | * You can also cause all additional macro instances to be immediately cancelled by setting a very short timeout (1 hundredth of a second) for the Semaphore Lock Action. When the Semaphore Local Action times out, it cancels the pending execution of that macro instance. | ||
| - | The //Semaphore actions// take a name, and different names can be used for different (independent) locks. | ||
| Semaphore Lock can be balanced by a Semaphore Unlock, but a Semaphore is implicitly unlocked when the macro that locked it completes. | Semaphore Lock can be balanced by a Semaphore Unlock, but a Semaphore is implicitly unlocked when the macro that locked it completes. | ||
action/Semaphore_Lock.txt · Last modified: 2022/10/30 21:42 by peternlewis
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