FIRST_IPADDRESS Macro

Public Function FIRST_IPADDRESS (ByVal ipAddress As Long) As Long
	FIRST_IPADDRESS = Val("&H" & Left(Right("00000000" & Hex(ipAddress), 8), 2))
End Function

Description & Usage

FIRST_IPADDRESS extracts the first field (field 0) from an IP address packed inside a 32-bit integer. The IP address must be in host byte order.

Return Value

The macro returns the value of the first field of the IP address.

Visual Basic-Specific Issues

Although it may seem unusual to use string operations for what would otherwise be a mathematical computation, it is necessary to implement FIRST_IPADDRESS this way in VB. Other methods to perform this task can fail for large inputs because VB interprets them as negative values, which causes an equivalent mathematical computation to return an unwanted value.

Parameters

ipAddress

The IP address to get the first field of. The IP address must be packed into a 32-bit integer in host byte order.

See Also

FOURTH_IPADDRESS, SECOND_IPADDRESS, THIRD_IPADDRESS

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Last Modified: October 29, 2000
This page is copyright © 2000 Paul Kuliniewicz. Copyright Information Revised October 29, 2000
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