[pull] master from yhirose:master

README.md

@@ -990,6 +990,25 @@ auto res = cli.Get("/already%20encoded/path"); // Use pre-encoded paths
   - `true` (default): Automatically encodes spaces, plus signs, newlines, and other special characters
   - `false`: Sends paths as-is without encoding (useful for pre-encoded URLs)
 
+### Performance Note for Local Connections
+
+> [!WARNING]
+> On Windows systems with improperly configured IPv6 settings, using "localhost" as the hostname may cause significant connection delays (up to 2 seconds per request) due to DNS resolution issues. This affects both client and server operations. For better performance when connecting to local services, use "127.0.0.1" instead of "localhost".
+> 
+> See: https://github.com/yhirose/cpp-httplib/issues/366#issuecomment-593004264
+
+```cpp
+// May be slower on Windows due to DNS resolution delays
+httplib::Client cli("localhost", 8080);
+httplib::Server svr;
+svr.listen("localhost", 8080);
+
+// Faster alternative for local connections
+httplib::Client cli("127.0.0.1", 8080);
+httplib::Server svr;
+svr.listen("127.0.0.1", 8080);
+```
+
 Compression
 -----------
 
@@ -1141,6 +1160,24 @@ Serving HTTP on 0.0.0.0 port 80 ...
 NOTE
 ----
 
+### Regular Expression Stack Overflow
+
+> [!CAUTION]
+> When using complex regex patterns in route handlers, be aware that certain patterns may cause stack overflow during pattern matching. This is a known issue with `std::regex` implementations and affects the `dispatch_request()` method.
+> 
+> ```cpp
+> // This pattern can cause stack overflow with large input
+> svr.Get(".*", handler);
+> ```
+> 
+> Consider using simpler patterns or path parameters to avoid this issue:
+> 
+> ```cpp
+> // Safer alternatives
+> svr.Get("/users/:id", handler);           // Path parameters
+> svr.Get(R"(/api/v\d+/.*)", handler);     // More specific patterns
+> ```
+
 ### g++
 
 g++ 4.8 and below cannot build this library since `<regex>` in the versions are [broken](https://stackoverflow.com/questions/12530406/is-gcc-4-8-or-earlier-buggy-about-regular-expressions).

httplib.h

@@ -8,7 +8,7 @@
 #ifndef CPPHTTPLIB_HTTPLIB_H
 #define CPPHTTPLIB_HTTPLIB_H
 
-#define CPPHTTPLIB_VERSION "0.22.0"
+#define CPPHTTPLIB_VERSION "0.23.0"
 
 /*
  * Platform compatibility check
@@ -3215,13 +3215,31 @@ inline int poll_wrapper(struct pollfd *fds, nfds_t nfds, int timeout) {
 
 template <bool Read>
 inline ssize_t select_impl(socket_t sock, time_t sec, time_t usec) {
+#ifdef __APPLE__
+  if (sock >= FD_SETSIZE) { return -1; }
+
+  fd_set fds, *rfds, *wfds;
+  FD_ZERO(&fds);
+  FD_SET(sock, &fds);
+  rfds = (Read ? &fds : nullptr);
+  wfds = (Read ? nullptr : &fds);
+
+  timeval tv;
+  tv.tv_sec = static_cast<long>(sec);
+  tv.tv_usec = static_cast<decltype(tv.tv_usec)>(usec);
+
+  return handle_EINTR([&]() {
+    return select(static_cast<int>(sock + 1), rfds, wfds, nullptr, &tv);
+  });
+#else
   struct pollfd pfd;
   pfd.fd = sock;
   pfd.events = (Read ? POLLIN : POLLOUT);
 
   auto timeout = static_cast<int>(sec * 1000 + usec / 1000);
 
   return handle_EINTR([&]() { return poll_wrapper(&pfd, 1, timeout); });
+#endif
 }
 
 inline ssize_t select_read(socket_t sock, time_t sec, time_t usec) {
@@ -3234,6 +3252,36 @@ inline ssize_t select_write(socket_t sock, time_t sec, time_t usec) {
 
 inline Error wait_until_socket_is_ready(socket_t sock, time_t sec,
                                         time_t usec) {
+#ifdef __APPLE__
+  if (sock >= FD_SETSIZE) { return Error::Connection; }
+
+  fd_set fdsr, fdsw;
+  FD_ZERO(&fdsr);
+  FD_ZERO(&fdsw);
+  FD_SET(sock, &fdsr);
+  FD_SET(sock, &fdsw);
+
+  timeval tv;
+  tv.tv_sec = static_cast<long>(sec);
+  tv.tv_usec = static_cast<decltype(tv.tv_usec)>(usec);
+
+  auto ret = handle_EINTR([&]() {
+    return select(static_cast<int>(sock + 1), &fdsr, &fdsw, nullptr, &tv);
+  });
+
+  if (ret == 0) { return Error::ConnectionTimeout; }
+
+  if (ret > 0 && (FD_ISSET(sock, &fdsr) || FD_ISSET(sock, &fdsw))) {
+    auto error = 0;
+    socklen_t len = sizeof(error);
+    auto res = getsockopt(sock, SOL_SOCKET, SO_ERROR,
+                          reinterpret_cast<char *>(&error), &len);
+    auto successful = res >= 0 && !error;
+    return successful ? Error::Success : Error::Connection;
+  }
+
+  return Error::Connection;
+#else
   struct pollfd pfd_read;
   pfd_read.fd = sock;
   pfd_read.events = POLLIN | POLLOUT;
@@ -3255,6 +3303,7 @@ inline Error wait_until_socket_is_ready(socket_t sock, time_t sec,
   }
 
   return Error::Connection;
+#endif
 }
 
 inline bool is_socket_alive(socket_t sock) {
@@ -8001,6 +8050,16 @@ Server::process_request(Stream &strm, const std::string &remote_addr,
   res.version = "HTTP/1.1";
   res.headers = default_headers_;
 
+#ifdef __APPLE__
+  // Socket file descriptor exceeded FD_SETSIZE...
+  if (strm.socket() >= FD_SETSIZE) {
+    Headers dummy;
+    detail::read_headers(strm, dummy);
+    res.status = StatusCode::InternalServerError_500;
+    return write_response(strm, close_connection, req, res);
+  }
+#endif
+
   // Request line and headers
   if (!parse_request_line(line_reader.ptr(), req) ||
       !detail::read_headers(strm, req.headers)) {