WinAPI: How to enumerate processes?
Q: How to enumerate currently running processes?
A: One method is by using Process Status API (PSAPI).
Example
Code:
#include <list>
#include <iostream>
#include <Windows.h>
#include <Psapi.h>
#pragma comment(lib, "Psapi.lib")
// Note: linking to Psapi.lib is not necessary if the target system is Windows 7 or newer
DWORD PSAPI_EnumProcesses(std::list<DWORD>& listProcessIDs, DWORD dwMaxProcessCount)
{
DWORD dwRet = NO_ERROR;
listProcessIDs.clear();
DWORD *pProcessIds = new DWORD[dwMaxProcessCount];
DWORD cb = dwMaxProcessCount * sizeof(DWORD);
DWORD dwBytesReturned = 0;
// call PSAPI EnumProcesses
if (::EnumProcesses(pProcessIds, cb, &dwBytesReturned))
{
// push returned process IDs into the output list
const int nSize = dwBytesReturned / sizeof(DWORD);
for(int nIndex = 0; nIndex < nSize; nIndex++)
{
listProcessIDs.push_back(pProcessIds[nIndex]);
}
}
else
{
dwRet = ::GetLastError();
}
delete[]pProcessIds;
return dwRet;
}
Code:
int main()
{
std::list<DWORD> listProcessIDs;
const DWORD dwMaxProcessCount = 1024;
DWORD dwRet = PSAPI_EnumProcesses(listProcessIDs, dwMaxProcessCount);
if(NO_ERROR == dwRet)
{
const std::list<DWORD>::const_iterator end = listProcessIDs.end();
std::list<DWORD>::const_iterator iter = listProcessIDs.begin();
for( ; iter != end; ++iter)
{
DWORD dwProcessID = *iter;
std::cout << "Process ID: " << dwProcessID << std::endl;
// NOTE: you can pass dwProcessID to ::OpenProcess and further get
// more process info by using the returned process handle
}
}
else
{
std::cout << "PSAPI_GetProcessesList failed. Error: " << dwRet << std::endl;
return dwRet;
}
return 0;
}
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WinAPI: How to enumerate processes? (2)
A: Another way is by using Tool Help Library.
Example
Code:
#include <list>
#include <iostream>
#include <Windows.h>
#include <Tlhelp32.h>
DWORD ToolHelp_EnumProcesses(std::list<PROCESSENTRY32>& listProcessInfo)
{
DWORD dwRet = NO_ERROR;
listProcessInfo.clear();
// take a snapshot of processes
DWORD dwFlags = TH32CS_SNAPPROCESS;
HANDLE hSnapshot = ::CreateToolhelp32Snapshot(dwFlags, 0);
if (INVALID_HANDLE_VALUE == hSnapshot)
{
return ::GetLastError();
}
PROCESSENTRY32 processEntry = {0};
processEntry.dwSize = sizeof(PROCESSENTRY32);
// get info for each process in the snapshot
if (::Process32First(hSnapshot, &processEntry))
{
do
{
listProcessInfo.push_back(processEntry);
} while (::Process32Next(hSnapshot, &processEntry));
}
else
{
dwRet = ::GetLastError();
}
::CloseHandle(hSnapshot);
return dwRet;
}
Code:
int main()
{
std::list<PROCESSENTRY32> listProcessInfo;
DWORD dwRet = ToolHelp_EnumProcesses(listProcessInfo);
if(NO_ERROR == dwRet)
{
const std::list<PROCESSENTRY32>::const_iterator end = listProcessInfo.end();
std::list<PROCESSENTRY32>::const_iterator iter = listProcessInfo.begin();
for (; iter != end; ++iter)
{
const PROCESSENTRY32& processEntry = *iter;
// NOTE: UNICODE & _UNICODE preprocessor constants are defined in this project
std::wcout << L"Process ID: " << processEntry.th32ProcessID << std::endl;
std::wcout << L"Exe file name: " << processEntry.szExeFile << std::endl;
std::wcout << L"Parent process ID: " << processEntry.th32ParentProcessID << std::endl;
std::wcout << L"Threads count: " << processEntry.cntThreads << std::endl;
// ...
}
}
else
{
std::cout << "ToolHelp_EnumProcesses falied. Error: " << dwRet << std::endl;
return dwRet;
}
return 0;
}
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WinAPI: How to enumerate processes? (3)
A: Also we can use WTSEnumerateProcesses or WTSEnumerateProcessesEx from Remote Desktop Services API (formerly known as Windows Terminal Services API).
Example
Code:
#include <iostream>
#include <list>
#include <string>
#include <Windows.h>
// Windows Terminal Server API header & lib
#include <Wtsapi32.h>
#pragma comment(lib, "Wtsapi32.lib")
class CProcessInfo
{
DWORD m_dwProcessId;
DWORD m_dwSessionId;
std::wstring m_strProcessName;
public:
CProcessInfo(WTS_PROCESS_INFO& processInfo)
: m_dwProcessId(processInfo.ProcessId),
m_dwSessionId(processInfo.SessionId),
m_strProcessName(processInfo.pProcessName)
{
}
DWORD GetProcessId() const {return m_dwProcessId;}
DWORD GetSessionId() const {return m_dwSessionId;}
std::wstring GetProcessName() const {return m_strProcessName;}
};
Code:
DWORD RDSAPI_EnumProcesses(std::list<CProcessInfo>& listProcessInfo)
{
listProcessInfo.clear(); // clear output array
HANDLE hServer = WTS_CURRENT_SERVER_HANDLE; // local machine processes
PWTS_PROCESS_INFO pProcessInfo = NULL;
DWORD dwCount = 0;
// enumerate processes
if (!::WTSEnumerateProcesses(hServer, 0, 1, &pProcessInfo, &dwCount))
{
return ::GetLastError();
}
// push processes info into the output list
for (DWORD dwIndex = 0; dwIndex < dwCount; dwIndex++)
{
CProcessInfo processInfo(pProcessInfo[dwIndex]);
listProcessInfo.push_back(processInfo);
}
// free the memory allocated in WTSEnumerateProcesses
::WTSFreeMemory(pProcessInfo);
return NO_ERROR;
}
Code:
int main()
{
std::list<CProcessInfo> listProcessInfo;
DWORD dwRet = RDSAPI_EnumProcesses(listProcessInfo);
if (NO_ERROR == dwRet)
{
const std::list<CProcessInfo>::const_iterator end = listProcessInfo.end();
std::list<CProcessInfo>::const_iterator iter = listProcessInfo.begin();
for (; iter != end; ++iter)
{
const CProcessInfo& processInfo = *iter;
std::wcout << L"Process ID: " << processInfo.GetProcessId() << std::endl;
std::wcout << L"Process name: " << processInfo.GetProcessName() << std::endl;
std::wcout << L"Session ID: " << processInfo.GetSessionId() << std::endl;
}
}
else
{
std::wcout << L"RDSAPI_EnumProcesses failed. Error: " << dwRet << std::endl;
return dwRet;
}
return 0;
}
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