Method ThreadPool

source/src/httplib/httplib.h:10088–10122

ThreadPool implementation

// ThreadPool implementation
inline ThreadPool::ThreadPool(size_t n, size_t max_n, size_t mqr)
    : base_thread_count_(n), max_queued_requests_(mqr), idle_thread_count_(0),
      shutdown_(false) {
#ifndef CPPHTTPLIB_NO_EXCEPTIONS
  if (max_n != 0 && max_n < n) {
    std::string msg = "max_threads must be >= base_threads";
    throw std::invalid_argument(msg);
  }
#endif
  max_thread_count_ = max_n == 0 ? n : max_n;
  threads_.reserve(base_thread_count_);
#ifndef CPPHTTPLIB_NO_EXCEPTIONS
  try {
#endif
    for (size_t i = 0; i < base_thread_count_; i++) {
      threads_.emplace_back(std::thread([this]() { worker(false); }));
    }
#ifndef CPPHTTPLIB_NO_EXCEPTIONS
  } catch (...) {
    // If thread creation fails partway (e.g., pthread_create returns EAGAIN),
    // signal the workers we already spawned to exit and join them so the
    // vector destructor does not see joinable threads (which would call
    // std::terminate). Then rethrow so the caller learns of the failure.
    {
      std::unique_lock<std::mutex> lock(mutex_);
      shutdown_ = true;
    }
    cond_.notify_all();
    for (auto &t : threads_) {
      if (t.joinable()) { t.join(); }
    }
    throw;
  }
#endif
}

inline bool ThreadPool::enqueue(std::function<void()> fn) {
  {