cross os threading example

thread.h

void* thread (void* (callback)(void* data), void* data);
void join (void* p);

#ifdef _WIN32
#include <windows.h>

void* thread (void* (callback)(void* data), void* data) {
    HANDLE p = CreateThread(NULL, 0, callback, data, 0, NULL);
    return p;
}

void join (void* p) {
    if (p) {
        WaitForSingleObject(p, INFINITE);
        CloseHandle((HANDLE) p);
    }
}

#else
#include <pthread.h>
#include <unistd.h>

void* thread (void* (callback)(void* data), void* data) {
    pthread_t p;
    pthread_create(&p, NULL, callback, data);
    return (void*)p;
}

void join (void* p) {
    pthread_join((pthread_t) p, NULL);
}
#endif

thread_example.c

#include <stdio.h>
#include "thread.h"

void* hello_world(void* data) {
    printf("hello %s\n", data);
}

int main () {
    char* world = "world";
    void* server = thread(hello_world, (void*) world);
    join(server);

    return 0;
}