WriteULong64ToUserRelease function (usermode_accessors.h)

The WriteULong64ToUserRelease function safely writes a ULONG64 value to user-mode memory with release semantics.

Syntax

void WriteULong64ToUserRelease(
  volatile ULONG64 *Destination,
  ULONG64          Value
);

Parameters

Destination

[out] A pointer to the user-mode memory ___location where the ULONG64 value will be written.

Value

[in] The ULONG64 value to write to the destination memory ___location.

Return value

None

Remarks

This function provides a safe way to write a ULONG64 value to user-mode memory. It ensures the provided address is a user-mode address before writing to it. The release semantics ensure that preceding memory operations can't be reordered after this write operation.

This function doesn't enforce alignment.

It raises a structured exception if the memory access fails, such as when the destination address isn't a user-mode address or is inaccessible.

This function will never be optimized away by the compiler, nor will the compiler create additional accesses to this memory ___location before the function is called or after the function returns (unless the source code explicitly performs these accesses). The memory access is performed with memory_order_release semantics.

This function works on all versions of Windows, not just the latest. You need to consume the latest WDK to get the function declaration from the usermode_accessors.h header. You also need the library (umaccess.lib) from the latest WDK. However, the resulting driver will run fine on older versions of Windows.

Requirements

See also

WriteULong64ToUser

ReadULong64FromUserAcquire