获取CPU使用率的C代码

#include <Windows.h> #include <Winternl.h> #include <stdio.h> #include "GetCpuUsage.h" BYTE g_NumOfProcessor = 0; LARGE_INTEGER g_liOldIdleTime; LARGE_INTEGER g_liOldSystemTime; PROCNTQSI NtQuerySystemInformation; int InitQuerySystem() { SYSTEM_BASIC_INFORMATION SysBaseInfo; LONG status; UINT iCpuUsage = 0; NtQuerySystemInformation = (PROCNTQSI)GetProcAddress(GetModuleHandleA("ntdll"), "NtQuerySystemInformation"); if (!NtQuerySystemInformation) { return -1; } // get number of processors in the system status = NtQuerySystemInformation(SystemBasicInformation, &SysBaseInfo,sizeof(SysBaseInfo),NULL); if (status != NO_ERROR) { return -2; } g_NumOfProcessor = SysBaseInfo.bKeNumberProcessors; if(GetCpuUsage(&iCpuUsage) != 0) { return -3; } return 0; } int GetCpuUsage(UINT *iUsages) { SYSTEM_PERFORMANCE_INFORMATION SysPerfInfo; SYSTEM_TIME_INFORMATION SysTimeInfo; double dbIdleTime; double dbSystemTime; LONG status; status = NtQuerySystemInformation(SystemTimeInformation, &SysTimeInfo,sizeof(SysTimeInfo),0); if (status!=NO_ERROR) { return -1; } // get new CPU's idle time status = NtQuerySystemInformation(SystemPerformanceInformation, &SysPerfInfo,sizeof(SysPerfInfo),NULL); if (status != NO_ERROR) { return -1; } // if it's a first call - skip it if (g_liOldIdleTime.QuadPart != 0) { // CurrentValue = NewValue - OldValue dbIdleTime = Li2Double(SysPerfInfo.liIdleTime) - Li2Double(g_liOldIdleTime); dbSystemTime = Li2Double(SysTimeInfo.liKeSystemTime) - Li2Double(g_liOldSystemTime); // CurrentCpuIdle = IdleTime / SystemTime dbIdleTime = dbIdleTime / dbSystemTime; // CurrentCpuUsage% = 100 - (CurrentCpuIdle * 100) / NumberOfProcessors dbIdleTime = 100.0 - dbIdleTime * 100.0 / (double)g_NumOfProcessor + 0.5; *iUsages = (UINT)dbIdleTime; } // store new CPU's idle and system time g_liOldIdleTime = SysPerfInfo.liIdleTime; g_liOldSystemTime = SysTimeInfo.liKeSystemTime; return 0; } /* { CStatic * showratebox = (CStatic *)pParam; NtQuerySystemInformation = (PROCNTQSI)GetProcAddress(GetModuleHandle("ntdll"), "NtQuerySystemInformation"); if (!NtQuerySystemInformation) return 0; status = NtQuerySystemInformation(SystemBasicInformation,&SysBaseInfo,sizeof(SysBaseInfo),NULL); if (status != NO_ERROR) return 0; while(stopflag == FALSE) { status = NtQuerySystemInformation(SystemTimeInformation,&SysTimeInfo,sizeof(SysTimeInfo),0); if (status!=NO_ERROR) return 0; status = NtQuerySystemInformation(SystemPerformanceInformation,&SysPerfInfo,sizeof(SysPerfInfo),NULL); if (status != NO_ERROR) return 0; if (liOldIdleTime.QuadPart != 0) { dbIdleTime = Li2Double(SysPerfInfo.liIdleTime) - Li2Double(liOldIdleTime); dbSystemTime = Li2Double(SysTimeInfo.liKeSystemTime) - Li2Double(liOldSystemTime); dbIdleTime = dbIdleTime / dbSystemTime; // CurrentCpuUsage% = 100 - (CurrentCpuIdle * 100) / NumberOfProcessors dbIdleTime = 100.0 - dbIdleTime * 100.0 / (double)SysBaseInfo.bKeNumberProcessors + 0.5; showrate.Format("%d%%",(UINT)dbIdleTime); showratebox->SetWindowText(showrate); m_HistogramCtrl.SetPos((UINT)dbIdleTime); } liOldIdleTime = SysPerfInfo.liIdleTime; liOldSystemTime = SysTimeInfo.liKeSystemTime; Sleep(1000); } return 0; } */