SYSTEM_INFO structure (sysinfoapi.h)

Article
09/23/2022

Contains information about the current computer system. This includes the architecture and type of the processor, the number of processors in the system, the page size, and other such information.

Syntax

typedef struct _SYSTEM_INFO {
  union {
    DWORD dwOemId;
    struct {
      WORD wProcessorArchitecture;
      WORD wReserved;
    } DUMMYSTRUCTNAME;
  } DUMMYUNIONNAME;
  DWORD     dwPageSize;
  LPVOID    lpMinimumApplicationAddress;
  LPVOID    lpMaximumApplicationAddress;
  DWORD_PTR dwActiveProcessorMask;
  DWORD     dwNumberOfProcessors;
  DWORD     dwProcessorType;
  DWORD     dwAllocationGranularity;
  WORD      wProcessorLevel;
  WORD      wProcessorRevision;
} SYSTEM_INFO, *LPSYSTEM_INFO;

Members

DUMMYUNIONNAME

DUMMYUNIONNAME.dwOemId

An obsolete member that is retained for compatibility. Applications should use the wProcessorArchitecture branch of the union.

DUMMYUNIONNAME.DUMMYSTRUCTNAME

DUMMYUNIONNAME.DUMMYSTRUCTNAME.wProcessorArchitecture

The processor architecture of the installed operating system. This member can be one of the following values.

Value	Meaning
PROCESSOR_ARCHITECTURE_AMD64 9	x64 (AMD or Intel)
PROCESSOR_ARCHITECTURE_ARM 5	ARM
PROCESSOR_ARCHITECTURE_ARM64 12	ARM64
PROCESSOR_ARCHITECTURE_IA64 6	Intel Itanium-based
PROCESSOR_ARCHITECTURE_INTEL 0	x86
PROCESSOR_ARCHITECTURE_UNKNOWN 0xffff	Unknown architecture.

DUMMYUNIONNAME.DUMMYSTRUCTNAME.wReserved

This member is reserved for future use.

dwPageSize

The page size and the granularity of page protection and commitment. This is the page size used by the VirtualAlloc function.

lpMinimumApplicationAddress

A pointer to the lowest memory address accessible to applications and dynamic-link libraries (DLLs).

lpMaximumApplicationAddress

A pointer to the highest memory address accessible to applications and DLLs.

dwActiveProcessorMask

A mask representing the set of processors configured into the system. Bit 0 is processor 0; bit 31 is processor 31.

dwNumberOfProcessors

The number of logical processors in the current group. To retrieve the current processor group, use the GetLogicalProcessorInformation function.

Note For information about the physical processors shared by logical processors, call GetLogicalProcessorInformationEx with the RelationshipType parameter set to RelationProcessorPackage (3).

dwProcessorType

An obsolete member that is retained for compatibility. Use the wProcessorArchitecture, wProcessorLevel, and wProcessorRevision members to determine the type of processor.

PROCESSOR_INTEL_386 (386)

PROCESSOR_INTEL_486 (486)

PROCESSOR_INTEL_PENTIUM (586)

PROCESSOR_INTEL_IA64 (2200)

PROCESSOR_AMD_X8664 (8664)

PROCESSOR_ARM (Reserved)

dwAllocationGranularity

The granularity for the starting address at which virtual memory can be allocated. For more information, see VirtualAlloc.

wProcessorLevel

The architecture-dependent processor level. It should be used only for display purposes. To determine the feature set of a processor, use the IsProcessorFeaturePresent function.

If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_INTEL, wProcessorLevel is defined by the CPU vendor.

If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_IA64, wProcessorLevel is set to 1.

wProcessorRevision

The architecture-dependent processor revision. The following table shows how the revision value is assembled for each type of processor architecture.

Processor	Value
Intel Pentium, Cyrix, or NextGen 586	The high byte is the model and the low byte is the stepping. For example, if the value is xxyy, the model number and stepping can be displayed as follows: Model xx, Stepping yy
Intel 80386 or 80486	A value of the form xxyz. If xx is equal to 0xFF, y - 0xA is the model number, and z is the stepping identifier. If xx is not equal to 0xFF, xx + 'A' is the stepping letter and yz is the minor stepping.
ARM	Reserved.

Processor

Value

Intel Pentium, Cyrix, or NextGen 586

The high byte is the model and the low byte is the stepping. For example, if the value is xxyy, the model number and stepping can be displayed as follows:

Model xx, Stepping yy

Intel 80386 or 80486

A value of the form xxyz.

If xx is equal to 0xFF, y - 0xA is the model number, and z is the stepping identifier.

If xx is not equal to 0xFF, xx + 'A' is the stepping letter and yz is the minor stepping.

ARM

Reserved.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps \| UWP apps]
Minimum supported server	Windows 2000 Server [desktop apps \| UWP apps]
Header	sysinfoapi.h (include Windows.h)

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