Add. Pass socket as lightuserdata if it not fit to Lua number.

src/lcmulti.c

@@ -380,7 +380,7 @@ static int lcurl_multi_timeout(lua_State *L){
 
 static int lcurl_multi_socket_action(lua_State *L){
   lcurl_multi_t *p = lcurl_getmulti(L);
-  curl_socket_t s  = lutil_optint64(L, 2, CURL_SOCKET_TIMEOUT);
+  curl_socket_t s  = lcurl_opt_os_socket(L, 2, CURL_SOCKET_TIMEOUT);
   CURLMcode code; int n, mask;
   lua_State *curL;
 
@@ -551,7 +551,7 @@ static int lcurl_multi_socket_callback(CURL *easy, curl_socket_t s, int what, vo
   lua_rawgetp(L, -1, easy);
   e = lcurl_geteasy_at(L, -1);
   lua_remove(L, -2);
-  lutil_pushint64(L, s);
+  lcurl_push_os_socket(L, s);
   lua_pushinteger(L, what);
 
   if(lua_pcall(L, n+2, 0, 0)){

src/lcutils.c

@@ -332,4 +332,58 @@ void lcurl_stack_dump (lua_State *L){
     i++;
   }
   fprintf(stderr, " ------------ Stack Dump Finished ------------\n" );
-}
+}
+
+curl_socket_t lcurl_opt_os_socket(lua_State *L, int idx, curl_socket_t def) {
+  if (lua_islightuserdata(L, idx))
+    return (curl_socket_t)lua_touserdata(L, idx);
+
+  return (curl_socket_t)lutil_optint64(L, idx, def);
+}
+
+void lcurl_push_os_socket(lua_State *L, curl_socket_t fd) {
+#if !defined(_WIN32)
+  lutil_pushint64(L, fd);
+#else /*_WIN32*/
+  /* Assumes that compiler can optimize constant conditions. MSVC do this. */
+
+  /*On Lua 5.3 lua_Integer type can be represented exactly*/
+#if LUA_VERSION_NUM >= 503
+  if (sizeof(curl_socket_t) <= sizeof(lua_Integer)) {
+    lua_pushinteger(L, (lua_Integer)fd);
+    return;
+  }
+#endif
+
+#if defined(LUA_NUMBER_DOUBLE) || defined(LUA_NUMBER_FLOAT)
+  /*! @todo test DBL_MANT_DIG, FLT_MANT_DIG */
+
+  if (sizeof(lua_Number) == 8) { /*we have 53 bits for integer*/
+    if ((sizeof(curl_socket_t) <= 6)) {
+      lua_pushnumber(L, (lua_Number)fd);
+      return;
+    }
+
+    if(((UINT_PTR)fd & 0x1FFFFFFFFFFFFF) == (UINT_PTR)fd)
+      lua_pushnumber(L, (lua_Number)fd);
+    else
+      lua_pushlightuserdata(L, (void*)fd);
+
+    return;
+  }
+
+  if (sizeof(lua_Number) == 4) { /*we have 24 bits for integer*/
+    if (((UINT_PTR)fd & 0xFFFFFF) == (UINT_PTR)fd)
+      lua_pushnumber(L, (lua_Number)fd);
+    else
+      lua_pushlightuserdata(L, (void*)fd);
+    return;
+  }
+#endif
+
+  lutil_pushint64(L, fd);
+  if (lcurl_opt_os_socket(L, -1, 0) != fd)
+    lua_pushlightuserdata(L, (void*)fd);
+
+#endif /*_WIN32*/
+}

src/lcutils.h

@@ -91,4 +91,8 @@ int lcurl_utils_apply_options(lua_State *L, int opt, int obj, int do_close,
 
 void lcurl_stack_dump (lua_State *L);
 
+curl_socket_t lcurl_opt_os_socket(lua_State *L, int idx, curl_socket_t def);
+
+void lcurl_push_os_socket(lua_State *L, curl_socket_t fd);
+
 #endif