From 6c673b21e5439087e3cdc9c3dd39eba2d99928c8 Mon Sep 17 00:00:00 2001
From: yhirose <yuji.hirose.bug@gmail.com>
Date: Wed, 15 Dec 2021 06:36:21 -0500
Subject: [PATCH] Adjust the way to check if the sockt is still alive.

---
 httplib.h | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/httplib.h b/httplib.h
index dc328fc..f81bcf2 100644
--- a/httplib.h
+++ b/httplib.h
@@ -2337,14 +2337,6 @@ inline bool wait_until_socket_is_ready(socket_t sock, time_t sec, time_t usec) {
 #endif
 }
 
-inline bool is_socket_alive(socket_t sock) {
-  if (detail::select_read(sock, 0, 0) == 0) {
-    return true;
-  }
-  char buf[1];
-  return recv(sock, &buf[0], sizeof(buf), MSG_PEEK) > 0;
-}
-
 class SocketStream : public Stream {
 public:
   SocketStream(socket_t sock, time_t read_timeout_sec, time_t read_timeout_usec,
@@ -5119,9 +5111,7 @@ Server::create_server_socket(const char *host, int port, int socket_flags,
         if (::bind(sock, ai.ai_addr, static_cast<socklen_t>(ai.ai_addrlen))) {
           return false;
         }
-        if (::listen(sock, CPPHTTPLIB_LISTEN_BACKLOG)) {
-          return false;
-        }
+        if (::listen(sock, CPPHTTPLIB_LISTEN_BACKLOG)) { return false; }
         return true;
       });
 }
@@ -5738,7 +5728,19 @@ inline bool ClientImpl::send(Request &req, Response &res, Error &error) {
 
     auto is_alive = false;
     if (socket_.is_open()) {
-      is_alive = detail::is_socket_alive(socket_.sock);
+      // Check if the socket is still alive.
+      {
+        auto val = detail::select_read(socket_.sock, 0, 0);
+        if (val < 0) {
+          return false;
+        } else if (val == 0) {
+          is_alive = true;
+        }
+        char buf[1];
+        is_alive =
+            detail::read_socket(socket_.sock, buf, sizeof(buf), MSG_PEEK) > 0;
+      }
+
       if (!is_alive) {
         // Attempt to avoid sigpipe by shutting down nongracefully if it seems
         // like the other side has already closed the connection Also, there