GetProcessWorkingSetSize function (memoryapi.h)

Article
02/22/2024

Retrieves the minimum and maximum working set sizes of the specified process.

Syntax

BOOL GetProcessWorkingSetSize(
  [in]  HANDLE  hProcess,
  [out] PSIZE_T lpMinimumWorkingSetSize,
  [out] PSIZE_T lpMaximumWorkingSetSize
);

Parameters

[in] hProcess

A handle to the process whose working set sizes will be obtained. The handle must have the PROCESS_QUERY_INFORMATION or PROCESS_QUERY_LIMITED_INFORMATION access right. For more information, see Process Security and Access Rights.

Windows Server 2003 and Windows XP: The handle must have the PROCESS_QUERY_INFORMATION access right.

[out] lpMinimumWorkingSetSize

A pointer to a variable that receives the minimum working set size of the specified process, in bytes. The virtual memory manager attempts to keep at least this much memory resident in the process whenever the process is active.

[out] lpMaximumWorkingSetSize

A pointer to a variable that receives the maximum working set size of the specified process, in bytes. The virtual memory manager attempts to keep no more than this much memory resident in the process whenever the process is active when memory is in short supply.

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

The "working set" of a process is the set of memory pages currently visible to the process in physical RAM memory. These pages are resident and available for an application to use without triggering a page fault. The minimum and maximum working set sizes affect the virtual memory paging behavior of a process.

Examples

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
    SIZE_T  dwMin, dwMax;
    HANDLE hProcess;

    if (argc != 2)
    {
        printf("This program requires a process ID as an argument.\n");
        return 1;
    }

    // Retrieve a handle to the process.

    hProcess = OpenProcess( PROCESS_QUERY_INFORMATION, 
                            FALSE, atoi(argv[1]));
     if (!hProcess)
    {
        printf( "OpenProcess failed (%d)\n", GetLastError() );
        return 1;
    }

    // Retrieve the working set size of the process.

    if (!GetProcessWorkingSetSize(hProcess, &dwMin, &dwMax))
    {
        printf("GetProcessWorkingSetSize failed (%d)\n",
            GetLastError());
        return 1;
    }

    printf("Process ID: %d\n", atoi(argv[1]));
    printf("Minimum working set: %lu KB\n", dwMin/1024);
    printf("Maximum working set: %lu KB\n", dwMax/1024);

    CloseHandle(hProcess);

    return 0;
}

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Header	memoryapi.h
Library	onecore.lib
DLL	Kernel32.dll