Enumerate Processes

Introduction

Enumerate processes via CreateToolhelp32Snapshot and Process32First/Process32Next. It will take a snapshot of all process running on the system and then iterate through the list of processes to find the process with the name specified.

#include <stdio.h>
#include <tlhelp32.h>
#include <windows.h>

ENUMRATOR_STATUS EnumProcessByName(IN LPCSTR lpProcessName, OUT DWORD *pdwProcessId)
{
        if (lpProcessName == NULL || pdwProcessId == NULL)
                return ENUMRATOR_STATUS_INVALID_PARAMETER;

        PROCESSENTRY32 pe32;
        pe32.dwSize = sizeof(PROCESSENTRY32);

        HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
        if (hSnapshot == INVALID_HANDLE_VALUE)
                return ENUMRATOR_STATUS_FAILED;

        if (!Process32First(hSnapshot, &pe32))
        {
                CloseHandle(hSnapshot);
                return ENUMRATOR_STATUS_FAILED;
        }

        do
        {
                // print process name
                wprintf(L"%s\n", pe32.szExeFile);
                if (stricmp(pe32.szExeFile, lpProcessName) == 0)
                {
                        *pdwProcessId = pe32.th32ProcessID;
                        printf("Process ID: %d\n", *pdwProcessId);
                        CloseHandle(hSnapshot);
                        return ENUMRATOR_STATUS_SUCCESS;
                }
        } while (Process32Next(hSnapshot, &pe32));

        CloseHandle(hSnapshot);
        return ENUMRATOR_STATUS_FAILED;
}