如何获得CPU使用率

　　NT/2000方法：

#include

#include

#include

#define SystemBasicInformation 0

#define SystemPerformanceInformation 2

#define SystemTimeInformation 3

#define Li2Double(x) ((double)((x).HighPart) * 4.294967296E9 + (double)((x).LowPart))

typedef strUCt

{

DWord dwUnknown1;

ULONG uKeMaximumIncrement;

ULONG uPageSize;

ULONG uMmNumberOfPhysicalPages;

ULONG uMmLowestPhysicalPage;

ULONG uMmHighestPhysicalPage;

ULONG uAllocationGranularity;

PVOID pLowestUserAddress;

PVOID pMmHighestUserAddress;

ULONG uKeActiveProcessors;

BYTE bKeNumberProcessors;

BYTE bUnknown2;

WORD wUnknown3;

} SYSTEM_BASIC_INFORMATION;

typedef struct

{

LARGE_INTEGER liIdleTime;

DWORD dwSpare[76];

} SYSTEM_PERFORMANCE_INFORMATION;

typedef struct

{

LARGE_INTEGER liKeBootTime;

LARGE_INTEGER liKeSystemTime;

LARGE_INTEGER liEXPTimeZoneBias;

ULONG uCurrentTimeZoneId;

DWORD dwReserved;

} SYSTEM_TIME_INFORMATION;

// ntdll!NtQuerySystemInformation (NT specific!)

//

// The function copies the system information of the

// specified type into a buffer

//

// NTSYSAPI

// NTSTATUS

// NTAPI

// NtQuerySystemInformation(

// IN UINT SystemInformationClass, // information type

// OUT PVOID SystemInformation, // pointer to buffer

// IN ULONG SystemInformationLength, // buffer size in bytes

// OUT PULONG ReturnLength OPTIONAL // pointer to a 32-bit

// // variable that receives

// // the number of bytes

// // written to the buffer

// );

typedef LONG (WINAPI *PROCNTQSI)(UINT,PVOID,ULONG,PULONG);

PROCNTQSI NtQuerySystemInformation;

void main(void)

{

SYSTEM_PERFORMANCE_INFORMATION SysPerfInfo;

SYSTEM_TIME_INFORMATION SysTimeInfo;

SYSTEM_BASIC_INFORMATION SysBaseInfo;

double dbIdleTime;

double dbSystemTime;

LONG status;

LARGE_INTEGER liOldIdleTime = {0,0};

LARGE_INTEGER liOldSystemTime = {0,0};

NtQuerySystemInformation = (PROCNTQSI)GetProcAddress(

GetModuleHandle("ntdll"),

"NtQuerySystemInformation"

);

if (!NtQuerySystemInformation)

return;

// get number of processors in the system

status = NtQuerySystemInformation(SystemBasicInformation,&SysBaseInfo,sizeof(SysBaseInfo),NULL);

if (status != NO_ERROR)

return;

printf("

CPU Usage (press any key to exit): ");

while(!_kbhit())

{

// get new system time

status = NtQuerySystemInformation(SystemTimeInformation,&SysTimeInfo,sizeof(SysTimeInfo),0);

if (status!=NO_ERROR)

return;

// get new CPU's idle time

status = NtQuerySystemInformation(SystemPerformanceInformation,&SysPerfInfo,sizeof(SysPerfInfo),NULL);

if (status != NO_ERROR)

return;

// if it's a first call - skip it

if (liOldIdleTime.QuadPart != 0)

{

// CurrentValue = NewValue - OldValue

&nb