SYSTEM_INFO  7_YQWZ 

The SYSTEM_INFO structure 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.

typedef struct _SYSTEM_INFO {  // sinf

    union { 

        DWORD  dwOemId;

        struct { 

            WORD wProcessorArchitecture;

            WORD wReserved;

        };

    };

    DWORD  dwPageSize;

    LPVOID lpMinimumApplicationAddress;

    LPVOID lpMaximumApplicationAddress;

    DWORD  dwActiveProcessorMask;

    DWORD  dwNumberOfProcessors;

    DWORD  dwProcessorType;

    DWORD  dwAllocationGranularity;

    WORD  wProcessorLevel;

    WORD  wProcessorRevision;

} SYSTEM_INFO;

Members

dwOemId

An obsolete member that is retained for compatibility with previous versions of Windows NT. Beginning with Windows NT 3.51 and the initial release of Windows 95, use the wProcessorArchitecture branch of the union.

Windows 95: The system always sets this member to zero, the value defined for PROCESSOR_ARCHITECTURE_INTEL.

wProcessorArchitecture

Specifies the system s processor architecture. This value can be one of the following values:

wReserved

Reserved for future use.

dwPageSize

Specifies the page size and the granularity of page protection and commitment. This is the page size used by the VirtualAlloc1M7V8GO function.

lpMinimumApplicationAddress

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

lpMaximumApplicationAddress

Pointer to the highest memory address accessible to applications and DLLs.

dwActiveProcessorMask

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

dwNumberOfProcessors

Specifies the number of processors in the system.

dwProcessorType

Windows 95:

Specifies the type of processor in the system.

Windows NT:

This member is no longer relevant, but is retained for compatibility with Windows 95 and previous versions of Windows NT. Use the wProcessorArchitecture, wProcessorLevel, and wProcessorRevision members to determine the type of processor.

This member is one of the following values:

dwAllocationGranularity

Specifies the granularity with which virtual memory is allocated. For example, a VirtualAlloc request to allocate 1 byte will reserve an address space of dwAllocationGranularity bytes. This value was hard coded as 64K in the past, but other hardware architectures may require different values.

wProcessorLevel

Windows 95: This member is not used.

Windows NT: Specifies the system s architecture-dependent processor level.

If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_INTEL, wProcessorLevel can be one of the following values:

If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_MIPS, wProcessorLevel is of the form 00xx, where xx is an 8-bit implementation number (bits 8-15 of the PRId register). The member can be the following value:

If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_ALPHA, wProcessorLevel is of the form xxxx, where xxxx is a 16-bit processor version number (the low-order 16 bits of a version number from the firmware). The member can be one of the following values:

If wProcessorArchitecture is PROCESSOR_ARCHITECTURE_PPC, wProcessorLevel is of the form xxxx, where xxxx is a 16-bit processor version number (the high-order 16 bits of the Processor Version Register). The member can be one of the following values:

wProcessorRevision

Windows 95: This member is not used.

Windows NT: Specifies an architecture-dependent processor revision. The following table shows how the revision value is assembled for each type of processor architecture.

Remarks

Beginning with Windows NT 3.51 and the initial release of Windows 95, the SYSTEM_INFO structure has changed as follows:

    The dwOemId member has been changed to a union. The union supports a new way to describe processor architecture used by Windows NT, while maintaining compatibility with Windows 95 and previous versions of Windows NT.

    The dwProcessorType member is now obsolete on Windows NT. It is still used on Windows 95.

    A previously reserved DWORD member at the end of the structure has been replaced by the wProcessorLevel and wProcessorRevision members. Windows 95 does not use these members.

See Also