| Value | Meaning |
|---|---|
| DEBUGSO_DEBUG | Record debugging information |
| BROADCASTSO_BROADCAST | Allow transmission of broadcast messages |
| REUSEADDRSO_REUSEADDR | Allow local reuse of address |
| LINGERSO_LINGER | Linger on close if unsent data is present |
| OOBINLINESO_OOBINLINE | Receive out-of-band data in band |
| SNDBUFSO_SNDBUF | Send buffer size |
| RCVBUFSO_RCVBUF | Receive buffer size |
| DONTROUTESO_DONTROUTE | Do not route |
| SNDTIMEOSO_SNDTIMEO | Send timeout |
| RCVTIMEOSO_RCVTIMEO | Receive timeout |
| ERRORSO_ERROR | Retrieve and clear error status |
| KEEPALIVESO_KEEPALIVE | Enable keep-alive packets |
| ACCEPTCONNSO_ACCEPTCONN | Listen |
| RCVLOWATSO_RCVLOWAT | Minimum number of input bytes to process |
| SNDLOWATSO_SNDLOWAT | Minimum number of output bytes to process |
| TYPESO_TYPE | Socket type |
| TCP_NODELAY.TCP_NODELAY | Disable the Nagle algorithm for send coalescing |
| IPV6_UNICAST_HOPS.IPV6_UNICAST_HOPS | IP unicast hop limit |
| IPV6_MULTICAST_IF.IPV6_MULTICAST_IF | IP multicast interface |
| IPV6_MULTICAST_LOOP.IPV6_MULTICAST_LOOP | IP multicast loopback |
| IPV6_MULTICAST_HOPS.IPV6_MULTICAST_HOPS | IP multicast hops |
| IPV6_JOIN_GROUP.IPV6_JOIN_GROUP | Add an IP group membership |
| IPV6_LEAVE_GROUP.IPV6_LEAVE_GROUP | Drop an IP group membership |
| IPV6_V6ONLY.IPV6_V6ONLY | Treat wildcard bind as AF_INET6-only |
Specifies a socket option: