Add c++ test using lambdas

testscpp.cpp

@@ -1,25 +1,40 @@
-//
-// Created by Shoaib Ahmed on 3/30/18.
-//
 #include <vector>
+#include <iostream>
+#include <chrono>
+#include <thread>
 #include "libdo.h"
 
-static int runs;
-
-bool cb(void *param) {
-    (void) param;
-    return true;
-}
-
-bool predicate(void *param) {
-    (void) param;
-    return (runs++ % 2) == 0;
-}
+static int run_after_iterations = 5;
 
 int main() {
+    int iterations = 0;
     auto d = do_init();
-    auto dw = do_work_when(cb, nullptr, predicate);
+    if (!d) {
+        exit(EXIT_FAILURE);
+    }
+
+    auto dw = do_work_when(
+            // Cannot capture, use void data ptr instead
+            [](void *data) {
+                std::cout << "> Work ran after " << *reinterpret_cast<int *>(data) << " iterations" << std::endl;
+                return true;
+            },
+            &iterations,
+            [](void *data) {
+                return (*reinterpret_cast<int *>(data)) >= run_after_iterations;
+            }
+    );
+    if (!dw) {
+        do_destroy(d);
+        exit(EXIT_FAILURE);
+    }
+
+    std::cout << "--- Work will run after " << run_after_iterations << " iterations ---" << std::endl;
     do_so(d, dw);
-    while (do_loop(d));
-    return 0;
+    while (do_loop(d)) {
+        iterations++;
+        std::this_thread::sleep_for(std::chrono::seconds(1));
+    }
+    do_destroy(d);
+    exit(EXIT_SUCCESS);
 }