ATOMIC_SWAP_UINT(9) | Kernel Developer's Manual | ATOMIC_SWAP_UINT(9) |

`atomic_swap_uint`

,
`atomic_swap_ulong`

,
`atomic_swap_ptr`

— atomic
swap operations

```
#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`);

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`.

`atomic_swap_uint`

(),
`atomic_swap_ulong`

(), and
`atomic_swap_ptr`

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

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

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

July 18, 2014 | OpenBSD-current |