RtlIpv4StringToAddressExA function (ip2string.h)
The RtlIpv4StringToAddressEx function converts a string representation of an IPv4 address and port number to a binary IPv4 address and port.
Syntax
NTSYSAPI NTSTATUS RtlIpv4StringToAddressExA(
[in] PCSTR AddressString,
[in] BOOLEAN Strict,
[out] in_addr *Address,
[out] PUSHORT Port
);
Parameters
[in] AddressString
A pointer to a buffer containing the NULL-terminated string representation of the IPv4 address followed by an optional colon and string representation of a port number.
[in] Strict
A value that indicates whether the string must be an IPv4 address represented in strict four-part dotted-decimal notation. If this parameter is TRUE, the string must be dotted-decimal with four parts. If this parameter is FALSE, any of four forms are allowed for the string representation of the Ipv4 address, with decimal, octal, or hexadecimal notation. See the Remarks section for details.
[out] Address
A pointer where the binary representation of the IPv4 address is to be stored. The IPv4 address is stored in network byte order.
[out] Port
A pointer where the binary representation of the port number is to be stored. The port number is returned in network byte order. If no port was specified in the string pointed to by the AddressString parameter, then the Port parameter is set to zero.
Return value
If the function succeeds, the return value is STATUS_SUCCESS.
If the function fails, the return value is one of the following error codes.
| Return code | Description |
|---|---|
|
An invalid parameter was passed to the function. This error is returned if the Strict parameter was set to TRUE, but the string pointed to by the AddressString parameter did not contain a four-part dotted-decimal string representation of an IPv4 address. This error is also returned if the string pointed to by the AddressString parameter did not contain a proper string representation of an IPv4 address. This error code is defined in the Ntstatus.h header file. |
Remarks
The RtlIpv4StringToAddressEx function is used to convert a string representation of the IPv4 address and port number to a binary IPv4 address and a port number. The IPv4 address is returned in network order (bytes ordered from left to right). The port number is returned in network order.
RtlIpv4StringToAddressEx is a convenience function that does not require that the Windows Sockets DLL be loaded to access a function provided in Windows Sockets to perform string to IP address conversion.
If the Strict parameter is set to TRUE, then the string pointed to by the AddressString parameter must be in strict dotted-decimal notation. This strict format requires that four parts are specified. Each part is interpreted as a decimal byte of data and assigned, from left to right, to the four bytes of an IPv4 address.
When the Strict parameter is set to FALSE, the string pointed to by the AddressString parameter may be in any of the several possible formats. When the buffer pointed to by AddressString parameter contains a three-part address string, the last part is interpreted as a 16-bit quantity and placed in the right most two bytes of the network address. This makes the three-part address format convenient for specifying Class B network addresses as "128.net.host".
When the buffer pointed to by AddressString parameter contains a two-part address string, the last part is interpreted as a 24-bit quantity and placed in the right most three bytes of the network address. This makes the two part address format convenient for specifying Class A network addresses as "net.host". When the buffer pointed to by AddressString parameter contains only a one-part address string, the value is stored directly in the network address without any byte rearrangement.
The buffer pointed to by the AddressString parameter may contain the IPv4 address string followed by an optional colon and the string representation of a port number. If a port number string is included in the buffer pointed to by AddressString parameter, the binary representation of the port number is returned in the Port parameter. If the buffer pointed to by AddressString parameter does not contain a port number, a zero is returned in the Port parameter.
When either UNICODE or _UNICODE is defined, RtlIpv4StringToAddressEx is defined to RtlIpv4StringToAddressExW, the Unicode version of this function. The AddressString parameter is defined to the PCWSTR data type.
When both UNICODE and _UNICODE are not defined, RtlIpv4StringToAddressEx is defined to RtlIpv4StringToAddressExA, the ANSI version of this function. The AddressString parameter is defined to the PCSTR data type.
The IN_ADDR structure is defined in the Inaddr.h header file.
An import library containing the RtlIpv4StringToAddressEx function is not included in the Microsoft Windows Software Development Kit (SDK) released for Windows Vista. The RtlIpv4StringToAddressEx function is included in the Ntdll.lib import library included in the Windows Driver Kit (WDK). An application could also use the GetModuleHandle and GetProcAddress functions to retrieve the function pointer from the Ntdll.dll and call this function.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista [desktop apps | UWP apps] |
| Minimum supported server | Windows Server 2008 [desktop apps | UWP apps] |
| Target Platform | Windows |
| Header | ip2string.h (include Mstcpip.h) |
| DLL | Ntdll.dll |
See also
GetModuleHandle
GetProcAddress
IN_ADDR
InetNtop
InetPton
LoadLibrary
RtlIpv4AddressToString
RtlIpv4AddressToStringEx
RtlIpv4StringToAddress
RtlIpv6AddressToString
RtlIpv6AddressToStringEx
RtlIpv6StringToAddress
RtlIpv6StringToAddressEx
inet_addr
inet_ntoa