Pass errors from udp_sendto to WiFiUDP::endPacket (#1696)

Author: igrr

libraries/ESP8266WiFi/src/WiFiUdp.cpp

@@ -188,8 +188,7 @@ int WiFiUDP::endPacket()
     if (!_ctx)
         return 0;
 
-    _ctx->send();
-    return 1;
+    return (_ctx->send()) ? 1 : 0;
 }
 
 size_t WiFiUDP::write(uint8_t byte)

libraries/ESP8266WiFi/src/include/UdpContext.h

@@ -257,7 +257,7 @@ class UdpContext
         return size;
     }
 
-    void send(ip_addr_t* addr = 0, uint16_t port = 0)
+    bool send(ip_addr_t* addr = 0, uint16_t port = 0)
     {
         size_t data_size = _tx_buf_offset;
         pbuf* tx_copy = pbuf_alloc(PBUF_TRANSPORT, data_size, PBUF_RAM);
@@ -284,9 +284,13 @@ class UdpContext
             _pcb->ttl = _multicast_ttl;
         }
 
-        udp_sendto(_pcb, tx_copy, addr, port);
+        err_t err = udp_sendto(_pcb, tx_copy, addr, port);
+        if (err != ERR_OK) {
+            DEBUGV(":ust rc=%d\r\n", err);
+        }
         _pcb->ttl = old_ttl;
         pbuf_free(tx_copy);
+        return err == ERR_OK;
     }
 
 private: