WSAEFAULT error when use getsockname function

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!

2 Answers

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) 

Instead of general struct sockaddr use the one specified for your protocol i.e. *struct sockaddr_in* for IPv4 address. See here for a complete example.