EmptyWorkingSet function (psapi.h)

Article
08/23/2022

Removes as many pages as possible from the working set of the specified process.

Syntax

BOOL EmptyWorkingSet(
  [in] HANDLE hProcess
);

Parameters

[in] hProcess

A handle to the process. The handle must have the PROCESS_QUERY_INFORMATION or PROCESS_QUERY_LIMITED_INFORMATION access right and the PROCESS_SET_QUOTA access right. For more information, see Process Security and Access Rights.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

You can also empty the working set by calling the SetProcessWorkingSetSize or SetProcessWorkingSetSizeEx function with the dwMinimumWorkingSetSize and dwMaximumWorkingSetSize parameters set to the value (SIZE_T)(-1).

Starting with Windows 7 and Windows Server 2008 R2, Psapi.h establishes version numbers for the PSAPI functions. The PSAPI version number affects the name used to call the function and the library that a program must load.

If PSAPI_VERSION is 2 or greater, this function is defined as K32EmptyWorkingSet in Psapi.h and exported in Kernel32.lib and Kernel32.dll. If PSAPI_VERSION is 1, this function is defined as K32EmptyWorkingSet in Psapi.h and exported in Psapi.lib and Psapi.dll as a wrapper that calls K32EmptyWorkingSet.

Programs that must run on earlier versions of Windows as well as Windows 7 and later versions should always call this function as K32EmptyWorkingSet. To ensure correct resolution of symbols, add Psapi.lib to the TARGETLIBS macro and compile the program with -DPSAPI_VERSION=1. To use run-time dynamic linking, load Psapi.dll.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	psapi.h
Library	Kernel32.lib on Windows 7 and Windows Server 2008 R2; Psapi.lib (if PSAPI_VERSION=1) on Windows 7 and Windows Server 2008 R2; Psapi.lib on Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP
DLL	Kernel32.dll on Windows 7 and Windows Server 2008 R2; Psapi.dll (if PSAPI_VERSION=1) on Windows 7 and Windows Server 2008 R2; Psapi.dll on Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP