Use the Synchronization VIs and functions to synchronize tasks executing in parallel and to pass data between parallel tasks.

Notifier Operations
Use the Notifier Operations functions to suspend the execution of a block diagram until you receive data from another section of the block diagram or from another VI running in the same application instance.
Queue Operations
Use the Queue Operations functions to create a queue for communicating data between sections of a block diagram or from another VI.
Semaphore
Use the Semaphore VIs to limit the number of tasks that can simultaneously operate on a shared (protected) resource. A protected resource or critical section of code might include writing to global variables or communicating with external instruments.
Rendezvous
Use the Rendezvous VIs to synchronize two or more separate, parallel tasks at specific points of execution. Each task that reaches the rendezvous waits until the specified number of tasks are waiting, at which point all tasks proceed with execution.
Occurrences
Use the Occurrences functions to control separate, synchronous activities.
First Call? Function
Indicates that a subVI or section of a block diagram is running for the first time. The First Call? function returns TRUE only the first time you call it after you click the Run button.
Synchronize Data Flow VI
Passes through the values of the input wires after the upstream code executes.

Parent topic: Programming

Parent topic: Data Communication

LabVIEW Programming Reference Manual