# PR_NotifyAll

Promotes all threads waiting on a specified monitor to a ready state.

## Syntax

```{code}
#include <prmon.h>

PRStatus PR_NotifyAll(PRMonitor *mon);
```

### Parameters

The function has the following parameter:

`mon`

: A reference to an existing structure of type {ref}`PRMonitor`. The
  monitor object referenced must be one for which the calling thread
  currently holds the lock.

### Returns

The function returns one of the following values:

- If successful, `PR_SUCCESS`.
- If unsuccessful, `PR_FAILURE`.

## Description

A call to {ref}`PR_NotifyAll` causes all of the threads waiting on the
monitor to be scheduled to be promoted to a ready state. If no threads
are waiting, the operation is no-op.

{ref}`PR_NotifyAll` should be used with some care. The expense of
scheduling multiple threads increases dramatically as the number of
threads increases.