Diff: source/drivers/MicroBitSerial.cpp

Revision:

67:99cfde195ff3

Parent:

66:2fc7d7c2fffc

--- a/source/drivers/MicroBitSerial.cpp	Wed Jul 13 12:18:46 2016 +0100
+++ b/source/drivers/MicroBitSerial.cpp	Wed Jul 13 12:18:47 2016 +0100
@@ -441,8 +441,9 @@
   *
   *         Defaults to SYNC_SLEEP.
   *
-  * @return the number of bytes written, or MICROBIT_SERIAL_IN_USE if another fiber
-  *         is using the serial instance for transmission.
+  * @return the number of bytes written, MICROBIT_SERIAL_IN_USE if another fiber
+  *         is using the serial instance for transmission, MICROBIT_INVALID_PARAMETER
+  *         if buffer is invalid, or the given bufferLen is <= 0.
   */
 int MicroBitSerial::send(ManagedString s, MicroBitSerialMode mode)
 {
@@ -471,14 +472,18 @@
   *
   *         Defaults to SYNC_SLEEP.
   *
-  * @return the number of bytes written, or MICROBIT_SERIAL_IN_USE if another fiber
-  *         is using the serial instance for transmission.
+  * @return the number of bytes written, MICROBIT_SERIAL_IN_USE if another fiber
+  *         is using the serial instance for transmission, MICROBIT_INVALID_PARAMETER
+  *         if buffer is invalid, or the given bufferLen is <= 0.
   */
 int MicroBitSerial::send(uint8_t *buffer, int bufferLen, MicroBitSerialMode mode)
 {
     if(txInUse())
         return MICROBIT_SERIAL_IN_USE;
 
+    if(bufferLen <= 0 || buffer == NULL)
+        return MICROBIT_INVALID_PARAMETER;
+
     lockTx();
 
     //lazy initialisation of our tx buffer