///

/// 根据程序名（全路径）获得进程ID(PID)
///

/// 程序完整路径+文件名
///

function GetPIDByProgramName(const APName: string): THandle;
var
isFound: boolean;
AHandle, AhProcess: THandle;
ProcessEntry32: TProcessEntry32;
APath: array[0..MAX_PATH] of char;
begin
try
Result := 0;
AHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
ProcessEntry32.dwSize := Sizeof(ProcessEntry32);
isFound := Process32First(AHandle, ProcessEntry32);

while isFound do
begin
AhProcess := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ,
false, ProcessEntry32.th32ProcessID);
GetModuleFileNameEx(AhProcess, 0, @APath[0], sizeof(APath));

if (UpperCase(StrPas(APath)) = UpperCase(APName)) or
(UpperCase(StrPas(ProcessEntry32.szExeFile)) = UpperCase(APName)) then
begin
Result := ProcessEntry32.th32ProcessID;
break;
end;
isFound := Process32Next(AHandle, ProcessEntry32);
CloseHandle(AhProcess);
end;
finally
CloseHandle(AHandle);
end;
end;

///

/// 获得CPU使用率
///

/// 进程PID
///
function GetCpuUsage(PID: cardinal): single;
const
cWaitTime = 200;
var
h: Cardinal;
mCreationTime, mExitTime, mKernelTime, mUserTime: _FILETIME;
TotalTime1, TotalTime2: int64;
begin
Result := -1;
{We need to get a handle of the process with PROCESS_QUERY_INFORMATION privileges.}
h := OpenProcess(PROCESS_QUERY_INFORMATION, false, PID);
try
{We can use the GetProcessTimes() function to get the amount of time the process has spent in kernel mode and user mode.}
GetProcessTimes(h, mCreationTime, mExitTime, mKernelTime, mUserTime);
TotalTime1 := int64(mKernelTime.dwLowDateTime or (mKernelTime.dwHighDateTime shr 32)) + int64(mUserTime.dwLowDateTime or (mUserTime.dwHighDateTime shr 32));

{Wait a little}
Sleep(cWaitTime);

GetProcessTimes(h, mCreationTime, mExitTime, mKernelTime, mUserTime); TotalTime2 := int64(mKernelTime.dwLowDateTime or (mKernelTime.dwHighDateTime shr 32)) +
int64(mUserTime.dwLowDateTime or (mUserTime.dwHighDateTime shr 32));

{This should work out nicely, as there were approx. 250 ms between the calls
and the result will be a percentage between 0 and 100}
Result := ((TotalTime2 - TotalTime1) / cWaitTime) / 100;

finally
CloseHandle(h);
end;
end;

引用到两个单元

Uses TlHelp32, PsAPI;

这里有一些隐含用途，比如：

1、查询某个程序是否在使用，判断GetPIDByProgramName返回的PID是否大于零。

2、根据CPU使用率大小决定是否终止程序。频频使用这个函数时候，建议最好用一个Thread Timer执行，

可减低TTimer带来的CPU使用率。


本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/aroc_lo/archive/2008/09/20/2956358.aspx