BluetoothSerial: check return value and return number of bytes written (espressif#1538)

Author: gohai

libraries/BluetoothSerial/src/BluetoothSerial.cpp

@@ -220,21 +220,24 @@ int BluetoothSerial::read(void)
 
 size_t BluetoothSerial::write(uint8_t c)
 {
- if (_spp_client){
- uint8_t buffer[1];
- buffer[0] = c;
- esp_spp_write(_spp_client, 1, buffer);
- return 1;
+ if (!_spp_client){
+ return 0;
  }
- return -1;
+
+ uint8_t buffer[1];
+ buffer[0] = c;
+ esp_err_t err = esp_spp_write(_spp_client, 1, buffer);
+ return (err == ESP_OK) ? 1 : 0;
 }
 
 size_t BluetoothSerial::write(const uint8_t *buffer, size_t size)
 {
- if (_spp_client){
- esp_spp_write(_spp_client, size, (uint8_t *)buffer);
+ if (!_spp_client){
+ return 0;
  }
- return size;
+
+ esp_err_t err = esp_spp_write(_spp_client, size, (uint8_t *)buffer);
+ return (err == ESP_OK) ? size : 0;
 }
 
 void BluetoothSerial::flush()