# PRMcastRequest

Structure used to specify values for the `PR_SockOpt_AddMember` and
`PR_SockOpt_DropMember` socket options that define a request to join
or leave a multicast group.

## Syntax

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

struct PRMcastRequest {
  PRNetAddr mcaddr;
  PRNetAddr ifaddr;
};

typedef struct PRMcastRequest PRMcastRequest;
```

### Fields

The structure has the following fields:

`mcaddr`

: IP multicast address of group.

`ifaddr`

: Local IP address of interface.

## Description

The `mcaddr` and `ifaddr` fields are of the type {ref}`PRNetAddr`, but
their `port` fields are ignored. Only the IP address (`inet.ip`)
fields are used.