MEMORYSTATUSEX structure (sysinfoapi.h)

Article
02/22/2024

Contains information about the current state of both physical and virtual memory, including extended memory. The GlobalMemoryStatusEx function stores information in this structure.

Syntax

typedef struct _MEMORYSTATUSEX {
  DWORD     dwLength;
  DWORD     dwMemoryLoad;
  DWORDLONG ullTotalPhys;
  DWORDLONG ullAvailPhys;
  DWORDLONG ullTotalPageFile;
  DWORDLONG ullAvailPageFile;
  DWORDLONG ullTotalVirtual;
  DWORDLONG ullAvailVirtual;
  DWORDLONG ullAvailExtendedVirtual;
} MEMORYSTATUSEX, *LPMEMORYSTATUSEX;

Members

dwLength

The size of the structure, in bytes. You must set this member before calling
GlobalMemoryStatusEx.

dwMemoryLoad

A number between 0 and 100 that specifies the approximate percentage of physical memory that is in use (0 indicates no memory use and 100 indicates full memory use).

ullTotalPhys

The amount of actual physical memory, in bytes.

ullAvailPhys

The amount of physical memory currently available, in bytes. This is the amount of physical memory that can be immediately reused without having to write its contents to disk first. It is the sum of the size of the standby, free, and zero lists.

ullTotalPageFile

The current committed memory limit for the system or the current process, whichever is smaller, in bytes. To get the system-wide committed memory limit, call GetPerformanceInfo.

ullAvailPageFile

The maximum amount of memory the current process can commit, in bytes. This value is equal to or smaller than the system-wide available commit value. To calculate the system-wide available commit value, call GetPerformanceInfo and subtract the value of CommitTotal from the value of CommitLimit.

ullTotalVirtual

The size of the user-mode portion of the virtual address space of the calling process, in bytes. This value depends on the type of process, the type of processor, and the configuration of the operating system. For example, this value is approximately 2 GB for most 32-bit processes on an x86 processor and approximately 3 GB for 32-bit processes that are large address aware running on a system with 4-gigabyte tuning enabled.

ullAvailVirtual

The amount of unreserved and uncommitted memory currently in the user-mode portion of the virtual address space of the calling process, in bytes.

ullAvailExtendedVirtual

Reserved. This value is always 0.

Remarks

MEMORYSTATUSEX reflects the state of memory at the time of the call. It also reflects the size of the paging file at that time. The operating system can enlarge the paging file up to the maximum size set by the administrator.

The physical memory sizes returned include the memory from all nodes.

Examples

For an example, see the GlobalMemoryStatusEx function.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps only]
Minimum supported server	Windows Server 2003 [desktop apps only]
Header	sysinfoapi.h (include Windows.h)