## NAME

`atomic_swap_uint`

,
`atomic_swap_ulong`

,
`atomic_swap_ptr`

—
atomic swap operations

## SYNOPSIS

```
#include
<sys/atomic.h>
```

`unsigned int`

`atomic_swap_uint`

(`volatile
unsigned int *p`, `unsigned
int new`);

`unsigned long`

`atomic_swap_ulong`

(`volatile
unsigned long *p`,
`unsigned long new`);

`void *`

`atomic_swap_ptr`

(`volatile
void *p`, `void
*new`);

## DESCRIPTION

The atomic_swap set of functions provide an interface for atomically performing swap operations with respect to interrupts and multiple processors in the system.

The value referenced by the pointer `p` is
replaced by the value `new`.

## CONTEXT

`atomic_swap_uint`

(),
`atomic_swap_ulong`

(), and
`atomic_swap_ptr`

() can all be called during autoconf,
from process context, or from interrupt context.

## RETURN VALUES

These functions return the value at `p` as it
was before the swap operation.

## SEE ALSO

## HISTORY

The atomic_swap functions first appeared in NetBSD 5.0 and OpenBSD 5.5.