GetExtendedTcpTable function (iphlpapi.h)

The GetExtendedTcpTable function retrieves a table that contains a list of TCP endpoints available to the application.

Syntax

IPHLPAPI_DLL_LINKAGE DWORD GetExtendedTcpTable(
  [out]     PVOID           pTcpTable,
  [in, out] PDWORD          pdwSize,
  [in]      BOOL            bOrder,
  [in]      ULONG           ulAf,
  [in]      TCP_TABLE_CLASS TableClass,
  [in]      ULONG           Reserved
);

Parameters

[out] pTcpTable

A pointer to the table structure that contains the filtered TCP endpoints available to the application. For information about how to determine the type of table returned based on specific input parameter combinations, see the Remarks section later in this document.

[in, out] pdwSize

The estimated size of the structure returned in pTcpTable, in bytes. If this value is set too small, ERROR_INSUFFICIENT_BUFFER is returned by this function, and this field will contain the correct size of the structure.

[in] bOrder

A value that specifies whether the TCP connection table should be sorted. If this parameter is set to TRUE, the TCP endpoints in the table are sorted in ascending order, starting with the lowest local IP address. If this parameter is set to FALSE, the TCP endpoints in the table appear in the order in which they were retrieved.

The following values are compared (as listed) when ordering the TCP endpoints:

1. Local IP address
2. Local scope ID (applicable when the ulAf parameter is set to AF_INET6)
3. Local TCP port
4. Remote IP address
5. Remote scope ID (applicable when the ulAf parameter is set to AF_INET6)
6. Remote TCP port

[in] ulAf

The version of IP used by the TCP endpoints.

[in] TableClass

The type of the TCP table structure to retrieve. This parameter can be one of the values from the TCP_TABLE_CLASS enumeration.

On the Windows SDK released for Windows Vista and later, the organization of header files has changed and the TCP_TABLE_CLASS enumeration is defined in the Iprtrmib.h header file, not in the Iphlpapi.h header file.

The TCP_TABLE_CLASS enumeration value is combined with the value of the ulAf parameter to determine the extended TCP information to retrieve.

[in] Reserved

Reserved. This value must be zero.

Return value

If the call is successful, the value NO_ERROR is returned.

If the function fails, the return value is one of the following error codes.

Remarks

The table type returned by this function depends on the specific combination of the ulAf parameter and the TableClass parameter.

When the ulAf parameter is set to AF_INET, the following table indicates the TCP table type to retrieve in the structure pointed to by the pTcpTable parameter for each possible TableClass value.

When the ulAf parameter is set to AF_INET6, the following table indicates the TCP table type to retrieve in the structure pointed to by the pTcpTable parameter for each possible TableClass value.

The GetExtendedTcpTable function called with the ulAf parameter set to AF_INET6 and the TableClass set to TCP_TABLE_BASIC_LISTENER, TCP_TABLE_BASIC_CONNECTIONS, or TCP_TABLE_BASIC_ALL is not supported and returns ERROR_NOT_SUPPORTED.

On the Windows SDK released for Windows Vista and later, the organization of header files has changed. The various MIB_TCPTABLE structures are defined in the Tcpmib.h header file, not in the Iprtrmib.h header file. Note that the Tcpmib.h header file is automatically included in Iprtrmib.h, which is automatically included in the Iphlpapi.h header file. The Tcpmib.h and Iprtrmib.h header files should never be used directly.

Requirements

See also

MIB_TCP6TABLE

MIB_TCP6TABLE_OWNER_MODULE

MIB_TCP6TABLE_OWNER_PID

MIB_TCPTABLE

MIB_TCPTABLE_OWNER_MODULE

MIB_TCPTABLE_OWNER_PID

TCP_TABLE_CLASS