WSPAddressToString function

The WSPAddressToString function converts all components of a sockaddr structure into a human readable–numeric string representation of the address. This is used mainly for display purposes.


int WSPAddressToString(
  _In_    LPSOCKADDR         lpsaAddress,
  _In_    DWORD              dwAddressLength,
  _In_    LPWSAPROTOCOL_INFO lpProtocolInfo,
  _Out_   LPWSTR             lpszAddressString,
  _Inout_ LPDWORD            lpdwAddressStringLength,
  _Out_   LPINT              lpErrno


lpsaAddress [in]

Pointer to a sockaddr structure to translate into a string.

dwAddressLength [in]

Length of the address of sockaddr, in bytes.

lpProtocolInfo [in]

(required) WSAPROTOCOL_INFO structure associated with the provider that will do the translation.

lpszAddressString [out]

Buffer that receives the human readable–address string..

lpdwAddressStringLength [in, out]

Length of the AddressString buffer, in bytes. Returns the length of the string actually copied into the buffer. If the supplied buffer is not large enough, the function fails with a specific error of WSAEFAULT and this parameter is updated with the required size, in bytes.

lpErrno [out]

Pointer to the error code.

Return value

If no error occurs, WSPAddressToString returns zero. Otherwise, it returns SOCKET_ERROR, and a specific error code is available in lpErrno.

Error codeMeaning

The specified AddressString buffer is too small. Pass in a larger buffer.


The specified address is not a valid socket address, or its address family is not supported by the provider, or the specified lpProtocolInfo did not refer to a WSAPROTOCOL_INFO structure supported by the provider.




A layered service provider supplies an implementation of this function, but it is also a client of this function if and when it calls WSPAddressToString of the next layer in the protocol chain. Some special considerations apply to the lpProtocolInfo parameter as it is propagated down through the layers of the protocol chain.

If the next layer in the protocol chain is another layer, then, when the next layer's WSPAddressToString is called, this layer must pass to the next layer a lpProtocolInfo parameter that references the same unmodified WSAPROTOCOL_INFO structure with the same unmodified chain information. However, if the next layer is the base protocol (that is, the last element in the chain), this layer performs a substitution when calling the base provider's WSPAddressToString. In this case, the base provider's WSAPROTOCOL_INFO structure should be referenced by the lpProtocolInfo parameter. One vital benefit of this policy is that base service providers do not have to be aware of protocol chains.

This same propagation policy applies when propagating a WSAPROTOCOL_INFO structure through a layered sequence of other functions such as WSPDuplicateSocket, WSPStartup, WSPSocket, or WSPStringToAddress.


Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]



See also