dd_fastwrt Communications PDH Entry Point

Purpose

Allows kernel-mode users to transmit data.

Description

You use the dd_fastwrt entry point from a kernel-mode process to pass a write packet or string of packets to a PDH for transmission. To get the address of this entry point, you issue the fp_ioctl (CIO_GET_FASTWRT) kernel service.

The syntax and rules of usage are device-dependent and therefore not listed here. See the documentation on individual devices for more information. Some of the information that should be provided is:

• Number of packets allowed on a single fast write function call.
• Operational level from which the fast write function can be called.
• Syntax of the entry point.
• Trusted path usage. The device may not check every parameter.

When you call this entry point from a different adapter's receive interrupt level, you must ensure that the calling level is equal to or lower than the target adapter's operational level. This is the case when you forward packets from one port to another. To find out the operational level, see the documentation for the specific device.