How can a Win32 process get the pid of its parent?

Just in case anyone else runs across this question and is looking for a code sample, I had to do this recently for a Python library project I’m working on. Here’s the test/sample code I came up with:

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

int main(int argc, char *argv[]) 
    int pid = -1;
    HANDLE h = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    PROCESSENTRY32 pe = { 0 };
    pe.dwSize = sizeof(PROCESSENTRY32);

    //assume first arg is the PID to get the PPID for, or use own PID
    if (argc > 1) {
        pid = atoi(argv[1]);
    } else {
        pid = GetCurrentProcessId();

    if( Process32First(h, &pe)) {
        do {
            if (pe.th32ProcessID == pid) {
                printf("PID: %i; PPID: %i\n", pid, pe.th32ParentProcessID);
        } while( Process32Next(h, &pe));


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