The Windows Sockets WSASetService function registers or deregisters a service instance within one or more name spaces. This function can be used to affect a specific name space provider, all providers associated with a specific name space, or all providers across all name spaces.
INT WSASetService(
LPWSAQUERYSET lpqsRegInfo,
WSAESETSERVICEOP essOperation,
DWORD dwControlFlags
);
Flag | Meaning |
---|---|
SERVICE MULTIPLE | Controls scope of operation. When clear, service addresses are managed as a group. A register or deregister invalidates all existing addresses before adding the given address set. When set, the action is only performed on the given address set. A register does not invalidate existing addresses and a deregister only invalidates the given set of addresses. |
The available values for essOperation and dwControlFlags combine to give meanings as shown in the following table:
Operation | Flags | Service already exists | Service does not exist |
---|---|---|---|
RNRSERVICE _REGISTER |
none | Overwrite the object. Use only addresses specified. Object is REGISTERED. | Create a new object. Use only addresses specified. Object is REGISTERED. |
RNRSERVICE _REGISTER |
SERVICE _MULTIPLE |
Update object. Add new addresses to existing set. Object is REGISTERED. | Create a new object. Use all addresses specified. Object is REGISTERED. |
RNRSERVICE _DEREGISTER |
none | Remove all addresses, but do not remove object from name space. Object is DEREGISTERED. | WSASERVICE _NOT_FOUND |
RNRSERVICE _DEREGISTER |
SERVICE _MULTIPLE |
Update object. Remove only addresses that are specified. Only mark object as DEREGISTERED if no addresses present. Do not remove from the name space. | WSASERVICE _NOT_FOUND |
RNRSERVICE _DELETE |
none | Remove object from the name space. | WSASERVICE _NOT_FOUND |
RNRSERVICE _DELETE |
SERVICE _MULTIPLE |
Remove only addresses that are specified. Only remove object from the name space if no addresses remain. | WSASERVICE _NOT_FOUND |
SERVICE_MULTIPLE lets an application manage its addresses independently. This is useful when the application wants to manage its protocols individually or when the service resides on more than one machine. For instance, when a service uses more than one protocol, it may find that one listening socket aborts but the others remain operational. In this case, the service could deregister the aborted address without affecting the other addresses.
When using SERVICE_MULTIPLE, an application must not let stale addresses remain in the object. This can happen if the application aborts without issuing a DEREGISTER request. When a service registers, it should store its addresses. On its next invocation, the service should explicitly deregister these old stale addresses before registering new addresses.
The following table describes how service property data is represented in a WSAQUERYSET structure. Fields labeled as (Optional) can be supplied with a NULL pointer.
WSAQUERYSET Field Name | Service Property Description |
---|---|
Field Name | Service Property Description |
dwSize | Must be set to sizeof(WSAQUERYSET). This is a versioning mechanism. |
DwOutputFlags | Not applicable and ignored. |
LpszServiceInstanceName | Referenced string contains the service instance name. |
LpServiceClassId | The GUID corresponding to this service class. |
lpVersion | (Optional) Supplies service instance version number. |
LpszComment | (Optional) An optional comment string. |
DwNameSpace | See table below. |
LpNSProviderId | See table below. |
LpszContext | (Optional) Specifies the starting point of the query in a hierarchical name space. |
DwNumberOfProtocols | Ignored. |
LpafpProtocols | Ignored. |
LpszQueryString | Ignored. |
DwNumberOfCsAddrs | The number of elements in the array of CSADDRO_INFO structures referenced by lpcsaBuffer. |
LpcsaBuffer | A pointer to an array of CSADDRO_INFO structures that contain the address(es) that the service is listening on. |
lpBlob | (Optional) This is a pointer to a provider-specific entity. |
As illustrated below, the combination of the dwNameSpace and lpNSProviderId parameters determine that name space providers are affected by this function.
dwNameSpace | lpNSProviderId | Scope of Impact |
---|---|---|
Ignored | Non-NULL | The specified name space provider |
a valid name space ID | NULL | All name space providers that support the indicated name space |
NS_ALL | NULL | All name space providers |
The return value for WSASetService is zero if the operation was successful. Otherwise, the value SOCKET_ERROR is returned, and a specific error number can be retrieved by calling WSAGetLastError.
WSAEACCES | The calling routine does not have sufficient privileges to install the Service. |
WSAEINVAL | One or more required parameters were invalid or missing. |
WSANOTINITIALIZED | The WiS2_32.DLL has not been initialized. The application must first call WSAStartup before calling any Windows Sockets functions |
WSA NOT ENOUGH MEMORY | There was insufficient memory to perform the operation. |
WSASERVICE NOT FOUND | No such service is known. The service cannot be found in the specified name space. |
Windows NT: Yes
Windows: Yes
Windows CE: Unsupported.
Header: Declared in winsock2.h.
Import Library: Link with ws2_32.lib.