# PR_WaitForPollableEvent

Blocks the calling thread until the pollable event is set, and then
atomically unsetting the event before returning.

## Syntax

```{code}
NSPR_API(PRStatus) PR_WaitForPollableEvent(PRFileDesc *event);
```

### Parameter

The function has the following parameter:

`event`

: Pointer to a {ref}`PRFileDesc` structure previously created via a call
  to {ref}`PR_NewPollableEvent`.

### Returns

The function returns one of the following values:

- If successful, `PR_SUCCESS`.
- If unsuccessful, `PR_FAILURE`. The reason for the failure can be
  retrieved via {ref}`PR_GetError`.