| setsockopt |
| Prototype: |
#include <sys/types.h>
#include <sys/socket.h>
int setsockopt(int sd, int level, int optname, const void *optval,
socklen_t optlen);
|
| General Description: |
Change the behavior of socket sd. Every option has a value (some options are read- or write-only). You can set each option through optval and optlen. Socket options available for general, IP, TCP, and TCPv6. |
| Return Value: |
Zero (0) if everything goes well. If an error occurs, you can find the cause in errno. |
| Parameters |
| sd |
The socket to modify. |
| level |
The feature level (SOL_SOCKET, SOL_IP, SOL_TCP, SOL_IPV6). |
| optname |
The option to revise. |
| optval |
A pointer to the new value. |
| optlen |
The length of value in bytes. |
| Possible Errors |
| EBADF |
The argument sd is not a valid descriptor. |
| ENOTSOCK |
The argument sd is a file, not a socket. |
| ENOPROTOOPT |
The option is unknown at the level indicated. |
| EFAULT |
The address pointed to optval is not in a valid part of the process address space. |
| Examples |
const int TTL=128;
/*---Change the time-to-live to 128 hops---*/
if ( setsockopt(sd, SOL_IP, SO_TTL, &TTL, sizeof(TTL)) != 0 )
perror("setsockopt() failed");
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