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# CAPLfunctionTestWaitForSignalChange

# TestWaitForSignalChange

[Valid for](../../../Shared/FeatureAvailability.md): CANoe DE • CANoe4SW DE

## Function Syntax

```
long TestWaitForSignalChange(Signal aSignal, dword aTimeout);
```

## Description

Waits for an event from a signal which value is changed.

## Parameters

* **aSignal**: Signal to be queried
* **aTimeout**: Maximum time that should be waited \[ms]. Transmission of 0: no timeout controlling.

## Return Values

* **-2**: Signal is not valid
* **-1**: General error
* **0**: Wait state is exited due to a timeout
* **1**: Wait state is exited due to condition fulfillment

## Example

```c theme={null}
// waits 1000ms for change of signal "Velocity"
long result;
result = TestWaitForSignalChange(Node_SUT::Velocity, 1000);
```