getsockopt |
Prototype: |
#include <sys/types.h>
#include <sys/socket.h>
int getsockopt(int sd, int level, int optname, void *optval,
socklen_t *optlen);
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General Description: |
Get the socket configuration. 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 read. |
level |
The feature level (SOL_SOCKET, SOL_IP, SOL_TCP, SOL_IPV6). |
optname |
The option to revise. |
optval |
Place for value. |
optlen |
The length of value in bytes. This field is passed by reference. |
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 or optlen is not in a valid part of the process address space. |
Examples |
int error, size=sizeof(error);
if ( getsockopt(sd, SOL_SOCKET, SO_ERROR, &error, &size) != 0 )
perror("getsockopt() failed");
printf("socket error=%d\n", error);
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