DrvSynchronize function (winddi.h)

Article
02/22/2024

The DrvSynchronize function informs the driver that GDI needs to access a device-managed surface. This function allows asynchronous drawing operations performed by a device's coprocessor to be coordinated with GDI accesses.

Syntax

void DrvSynchronize(
  DHPDEV dhpdev,
  RECTL  *prcl
);

Parameters

dhpdev

Handle to the physical device's PDEV structure that identifies the device to be synchronized with GDI. This parameter is the device handle returned to GDI by DrvEnablePDEV.

prcl

Pointer to a RECTL structure. This parameter should be ignored by the driver.

Return value

None

Remarks

This function allows asynchronous drawing operations performed by a device's coprocessor to be coordinated with GDI accesses.

DrvSynchronize can be optionally implemented in display drivers. GDI calls this function only if it is hooked by EngAssociateSurface. GDI calls DrvSynchronize just before drawing directly onto the device surface. GDI will call DrvSynchronizeSurface instead of DrvSynchronize in drivers that implement both of these functions.

This function should return only when it is safe for GDI to access any device-managed surface. That is, DrvSynchronize should delay returning from the call until all asynchronous drawing operations have been completed by the device's coprocessor, thus indicating that it is safe for GDI to access any device-managed surface.

DrvSynchronize is intended to support devices that use a coprocessor for drawing. Such a device can treat some drawing operations as asynchronous, returning to GDI from the operation before the drawing is complete. If this is the case, it is possible that a subsequent drawing operation will be handled by GDI. In order for GDI to safely access device-managed surfaces, it must have a means of ensuring that any asynchronous rendering being done by the device's coprocessor is complete. By calling this function, GDI synchronizes access to a device-managed surface with the driver.

GDI will never call DrvSynchronize for device-managed surfaces. DrvSynchronize is not itself an output function.

Requirements

Requirement	Value
Target Platform	Desktop
Header	winddi.h (include Winddi.h)