V. Dyld/custom/lambda_capture_example.cpp

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+//g++ -std=c++11 lambda_capture_example.cpp -o lambda_capture_example
+
+/*
+This example demonstrates how lambda capture by reference [&] allows the lambda function to access and modify variables from the outer scope directly.
+
+1. We have a function withWritableMemory that simulates the process of making memory writable, executing some work, and then restoring memory protection.
+2. In the main function, we have variables x and y.
+3. We define a lambda function lambda capturing all variables by reference [&]().
+4. Inside the lambda, we modify the values of x and y.
+5. We call withWritableMemory and pass the lambda as an argument.
+6. The lambda is executed within the withWritableMemory function.
+7. After the lambda execution, we print the values of x and y to see the changes made inside the lambda.
+*/
+#include <iostream>
+
+void withWritableMemory(std::function<void()> work) {
+    std::cout << "Entering withWritableMemory function" << std::endl;
+    // Simulating the setup before making memory writable
+    std::cout << "Setting up memory..." << std::endl;
+
+    // Make memory writable
+
+    // Execute the provided work function
+    work();
+
+    // Restore memory protection
+    std::cout << "Restoring memory protection..." << std::endl;
+
+    std::cout << "Exiting withWritableMemory function" << std::endl;
+}
+
+int main() {
+    int x = 5;
+    int y = 3;
+
+    // Lambda function capturing all variables by reference
+    auto lambda = [&]() {
+        // Access and modify variables from the outer scope
+        x = x + 10;
+        y = y * 2;
+
+        std::cout << "Inside lambda: x = " << x << ", y = " << y << std::endl;
+    };
+
+    // Call the function with the lambda as an argument
+    withWritableMemory(lambda);
+
+    // After the lambda is executed
+    std::cout << "After lambda: x = " << x << ", y = " << y << std::endl;
+
+    return 0;
+}
+
+/*
+./lambda_capture_example
+
+Entering withWritableMemory function
+Setting up memory...
+Inside lambda: x = 15, y = 6
+Restoring memory protection...
+Exiting withWritableMemory function
+After lambda: x = 15, y = 6
+*/