The IOCTL_SERIAL_CONFIG_SIZE request returns information about configuration size.

Serial.sys always returns a configuration size of zero.

This request is obsolete and should not be used by new drivers for Microsoft Windows 2000 and later.

Major Code


Input Buffer


Input Buffer Length


Output Buffer

The AssociatedIrp.SystemBuffer member points to a client-allocated ULONG buffer that Serial.sys uses to output configuration size information.

Output Buffer Length

The Parameters.DeviceIoControl.OutputBufferLength is set to the size in bytes of a ULONG.

Input / Output Buffer

Input / Output Buffer Length

Status Block

The Information member is set to the size in bytes of a ULONG.

The Status member is set to one of the Generic Status Values for Serial Device Control Requests.


Header ntddser.h (include Ntddser.h)