WSADATA

typedef struct WSAData {
        WORD                    wVersion;
        WORD                    wHighVersion;
        char                    szDescription[WSADESCRIPTION_LEN+1];
        char                    szSystemStatus[WSASYS_STATUS_LEN+1];
        unsigned short          iMaxSockets;
        unsigned short          iMaxUdpDg;
        char FAR *              lpVendorInfo;
} WSADATA, FAR * LPWSADATA; 

The members of this structure are:

Parameters

wVersion

The version of the Windows Sockets specification that the WS2_32.DLL expects the caller to use.

wHighVersion

The highest version of the Windows Sockets specification that this DLL can support (also encoded as above). Normally this will be the same as wVersion.

szDescription

A null-terminated ASCII string into which the WS2_32.DLL copies a description of the Windows Sockets implementation. The text (up to 256 characters in length) can contain any characters except control and formatting characters: the most likely use that an application will put this to is to display it (possibly truncated) in a status message.

szSystemStatus

A null-terminated ASCII string into which the WS2_32.DLL copies relevant status or configuration information. The WS2_32.DLL should use this field only if the information might be useful to the user or support staff: it should not be considered as an extension of the szDescription field.

iMaxSockets

This field is retained for backward compatibility, but should be ignored for version 2 and later as no single value can be appropriate for all underlying service providers.

iMaxUdpDg

This value should be ignored for version 2 and onward. It is retained for compatibility with Windows Sockets specification 1.1, but should not be used when developing new applications. For the actual maximum message size specific to a particular Windows Sockets service provider and socket type, applications should use getsockopt to retrieve the value of option SO_MAX_MSG_SIZE after a socket has been created.

lpVendorInfo

This value should be ignored for version 2 and onward. It is retained for compatibility with Windows Sockets specification 1.1. Applications needing to access vendor-specific configuration information should use getsockopt to retrieve the value of option PVD_CONFIG. The definition of this value (if utilized) is beyond the scope of this specification.

Note An application should ignore the iMaxsockets, iMaxUdpDg, and lpVendorInfo fields in WSAData if the value in wVersion after a successful call to WSAStartup is at least 2. This is because the architecture of Windows Sockets has been changed in version 2 to support multiple providers, and WSAData no longer applies to a single vendor's stack. Two new socket options are introduced to supply provider-specific information: SO_MAX_MSG_SIZE (replaces the iMaxUdpDg element) and PVD_CONFIG (allows any other provider-specific configuration to occur).