Question

I have a problem using getsockname function. I have this code:

struct sockaddr sa;
int sa_len;
sa_len = sizeof(sa);
if (getsockname(socketfd, &sa, &sa_len) != SOCKET_ERROR)
{
   ///
}
else
{
   int error = WSAGetLastError();
   //error here WSAEFAULT always
}

As you can see, i always have error when use getsockname function. Error – WSAEFAULT. But why? structure and structure size are right, why this happens?

WSAEFAULT desc:

The name or the namelen parameter is not a valid part of the user
address space, or the namelen parameter is too small.

p.s. Application is 64 bit

Thanks!

Answer 1

Your struct sockaddr is too small to accept the socket address. Either use an appropriately sized struct, such as struct sockaddr_in, or better yet, use a struct sockaddr_storage, which is guaranteed to be large enough to contain the address. Using a sockaddr_storage also allows you to easily support both IPv4 and IPv6 with minimal adjustments.

Edited code:

struct sockaddr_storage sa;
int sa_len;
sa_len = sizeof(sa);
if (getsockname(socketfd, (struct sockaddr *)&sa, &sa_len) != SOCKET_ERROR)