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:
- Local IP address
- Local scope ID (applicable when the ulAf parameter is set to AF_INET6)
- Local TCP port
- Remote IP address
- Remote scope ID (applicable when the ulAf parameter is set to AF_INET6)
- Remote TCP port
[in] ulAf
The version of IP used by the TCP endpoints.
| Value | Meaning |
|---|---|
|
IPv4 is used. |
|
IPv6 is used. |
[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.
| Return code | Description |
|---|---|
|
An insufficient amount of space was allocated for the table. The size of the table is returned in the pdwSize parameter, and must be used in a subsequent call to this function in order to successfully retrieve the table.
This error is also returned if the pTcpTable parameter is NULL. |
|
An invalid parameter was passed to the function. This error is returned if the TableClass parameter contains a value that is not defined in the TCP_TABLE_CLASS enumeration. |
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.
| TableClass value | pTcpTable structure |
|---|---|
| TCP_TABLE_BASIC_ALL | MIB_TCPTABLE |
| TCP_TABLE_BASIC_CONNECTIONS | MIB_TCPTABLE |
| TCP_TABLE_BASIC_LISTENER | MIB_TCPTABLE |
| TCP_TABLE_OWNER_MODULE_ALL | MIB_TCPTABLE_OWNER_MODULE |
| TCP_TABLE_OWNER_MODULE_CONNECTIONS | MIB_TCPTABLE_OWNER_MODULE |
| TCP_TABLE_OWNER_MODULE_LISTENER | MIB_TCPTABLE_OWNER_MODULE |
| TCP_TABLE_OWNER_PID_ALL | MIB_TCPTABLE_OWNER_PID |
| TCP_TABLE_OWNER_PID_CONNECTIONS | MIB_TCPTABLE_OWNER_PID |
| TCP_TABLE_OWNER_PID_LISTENER | MIB_TCPTABLE_OWNER_PID |
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.
| TableClass value | pTcpTable structure |
|---|---|
| TCP_TABLE_OWNER_MODULE_ALL | MIB_TCP6TABLE_OWNER_MODULE |
| TCP_TABLE_OWNER_MODULE_CONNECTIONS | MIB_TCP6TABLE_OWNER_MODULE |
| TCP_TABLE_OWNER_MODULE_LISTENER | MIB_TCP6TABLE_OWNER_MODULE |
| TCP_TABLE_OWNER_PID_ALL | MIB_TCP6TABLE_OWNER_PID |
| TCP_TABLE_OWNER_PID_CONNECTIONS | MIB_TCP6TABLE_OWNER_PID |
| TCP_TABLE_OWNER_PID_LISTENER | MIB_TCP6TABLE_OWNER_PID |
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
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista, Windows XP with SP2 [desktop apps | UWP apps] |
| Minimum supported server | Windows Server 2008, Windows Server 2003 with SP1 [desktop apps | UWP apps] |
| Target Platform | Windows |
| Header | iphlpapi.h |
| Library | Iphlpapi.lib |
| DLL | Iphlpapi.dll |