prsocketoptiondata.md

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# PRSocketOptionData

Type for structure used with {ref}`PR_GetSocketOption` and

{ref}`PR_SetSocketOption` to specify options for file descriptors that

represent sockets.

## Syntax

```{code}

#include <prio.h>

typedef struct PRSocketOptionData

  PRSockOption option;

  union

     PRUintn ip_ttl;

     PRUintn mcast_ttl;

     PRUintn tos;

     PRBool non_blocking;

     PRBool reuse_addr;

     PRBool keep_alive;

     PRBool mcast_loopback;

     PRBool no_delay;

     PRSize max_segment;

     PRSize recv_buffer_size;

     PRSize send_buffer_size;

     PRLinger linger;

     PRMcastRequest add_member;

     PRMcastRequest drop_member;

     PRNetAddr mcast_if;

  } value;

} PRSocketOptionData;

```

### Fields

The structure has the following fields:

`ip_ttl`

: IP time-to-live.

`mcast_ttl`

: IP multicast time-to-live.

`tos`

: IP type-of-service and precedence.

`non_blocking`

: Nonblocking (network) I/O.

`reuse_addr`

: Allow local address reuse.

`keep_alive`

: Periodically test whether connection is still alive.

`mcast_loopback`

: IP multicast loopback.

`no_delay`

: Disable Nagle algorithm. Don't delay send to coalesce packets.

`max_segment`

: TCP maximum segment size.

`recv_buffer_size`

: Receive buffer size.

`send_buffer_size`

: Send buffer size.

`linger`

: Time to linger on close if data are present in socket send buffer.

`add_member`

: Join an IP multicast group.

`drop_member`

: Leave an IP multicast group.

`mcast_if`

: IP multicast interface address.

### Description

{ref}`PRSocketOptionData` is a name-value pair for a socket option. The

`option` field (of enumeration type {ref}`PRSockOption`) specifies the

name of the socket option, and the `value` field (a union of all

possible values) specifies the value of the option.