Runtime C++ — Download !free!

// Helper: Get file size size_t getFileSize(const std::string& path) struct stat stat_buf; if (stat(path.c_str(), &stat_buf) == 0) return stat_buf.st_size; return 0;

class DownloadManager public: using ProgressCallback = std::function<void(float progress, size_t downloaded, size_t total)>; using CompleteCallback = std::function<void(bool success, const std::string& error)>; struct DownloadOptions std::string url; std::string output_path; int timeout_seconds = 30; int max_retries = 3; bool resume_on_failure = true; std::string username; // Optional for auth std::string password; // Optional for auth std::string user_agent = "C++DownloadManager/1.0"; ; DownloadManager(); ~DownloadManager(); // Start async download void downloadAsync(const DownloadOptions& options, ProgressCallback progress = nullptr, CompleteCallback complete = nullptr); // Sync download with progress bool downloadSync(const DownloadOptions& options, ProgressCallback progress = nullptr); // Cancel active download void cancel(); // Check if download is active bool isActive() const return m_active; // Get last error std::string getLastError() const return m_lastError;

cmake_minimum_required(VERSION 3.10) project(DownloadManager) set(CMAKE_CXX_STANDARD 17)

This is production-ready code that handles real-world download scenarios efficiently.

int DownloadManager::progressCallback(void* userp, curl_off_t dltotal, curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow) auto* ctx = static_cast<DownloadContext*>(userp); if (dltotal > 0) ctx->total_bytes = dltotal; if (ctx->progress_cb) float progress = (float)dlnow / dltotal; ctx->progress_cb(progress, dlnow, dltotal); return 0; // Return non-zero to cancel

add_executable(downloader download_manager.cpp)