diff --git a/pigpio.c b/pigpio.c
index 82803f5..de8f142 100644
--- a/pigpio.c
+++ b/pigpio.c
@@ -25,7 +25,7 @@ OTHER DEALINGS IN THE SOFTWARE.
 For more information, please refer to <http://unlicense.org/>
 */
 
-/* pigpio version 8 */
+/* pigpio version 9 */
 
 #include <stdio.h>
 #include <string.h>
@@ -583,7 +583,7 @@ typedef struct
    callbk_t func;
    unsigned ex;
    void *   userdata;
-   unsigned timeout;
+   int      timeout;
    uint32_t tick;
 } gpioAlert_t;
 
diff --git a/pigpio.h b/pigpio.h
index 8ab7c67..9b46ead 100644
--- a/pigpio.h
+++ b/pigpio.h
@@ -26,7 +26,7 @@ For more information, please refer to <http://unlicense.org/>
 */
 
 /*
-This version is for pigpio version 8
+This version is for pigpio version 9
 */
 
 #ifndef PIGPIO_H
@@ -84,7 +84,7 @@ This version is for pigpio version 8
 
 #include <stdint.h>
 
-#define PIGPIO_VERSION 8
+#define PIGPIO_VERSION 9
 
 /*-------------------------------------------------------------------------*/
 
@@ -841,7 +841,7 @@ int gpioWaveClear(void);
    The fields specify
 
    1) the gpios to be switched on at the start of the pulse.
-   2) the gpios to be switched off at the end of the pulse.
+   2) the gpios to be switched off at the start of the pulse.
    3) the delay in microseconds before the next pulse.
 
    Any or all the fields can be zero.  It doesn't make any sense to