Table Of Contents
First Call? (G Dataflow)
Indicates whether the diagram or subdiagram containing this node is running for the first time since the top-level caller began execution.
You can place First Call? in multiple locations within a program, such as the diagram of a VI, a subdiagram of a Case Structure, inside a loop, or the diagram of a subVI.
First Call?
A Boolean value that indicates whether the diagram or subdiagram containing this node is running for the first time since the top-level caller began execution.
| True | This is the first time the diagram or subdiagram is running since the program began execution. |
| False | This is not the first time the diagram or subdiagram is running since the program began execution. |
Behavior for Multiple Top-Level Callers
First Call? returns True the first time the calling diagram or subdiagram runs after the first top-level calling VI starts running, such as when you click the Run button. If a second top-level caller calls the diagram or subdiagram while the first top-level caller is still running, First Call? does not return True a second time. After all the top-level callers become idle and a top-level caller starts again, First Call? returns True the first time the VI runs after the idle state.
Behavior with Reentrant VIs
A stateless reentrant VI has one instance of the VI per caller at compile time. Therefore, First Call? in a stateless reentrant VI returns True the first time a top-level caller calls each instance of the VI.
Where This Node Can Run:
Desktop OS: Windows
FPGA: DAQExpress does not support FPGA devices