3 files changed, 7 insertions, 8 deletions
diff --git a/libical/src/libical/icalduration.c b/libical/src/libical/icalduration.c
index 18a74396f5..250cd6e3d6 100644
--- a/libical/src/libical/icalduration.c
+++ b/libical/src/libical/icalduration.c
@@ -250,7 +250,7 @@ char* icaldurationtype_as_ical_string(struct icaldurationtype d)
 	    
 	}
     } else {
-	icalmemory_append_string(&buf, &buf_ptr, &buf_size, "PTS0");
+	icalmemory_append_string(&buf, &buf_ptr, &buf_size, d.is_neg ? "-PT0S" : "PT0S");
     }
  
     output_line = icalmemory_tmp_copy(buf);
@@ -274,7 +274,7 @@ int icaldurationtype_as_int(struct icaldurationtype dur)
 		  * (dur.is_neg==1? -1 : 1) ) ;
 } 
 
-struct icaldurationtype icaldurationtype_null_duration()
+struct icaldurationtype icaldurationtype_null_duration(void)
 {
     struct icaldurationtype d;
     
diff --git a/libical/src/libical/icalduration.h b/libical/src/libical/icalduration.h
index dd6e311f47..0450a081d3 100644
--- a/libical/src/libical/icalduration.h
+++ b/libical/src/libical/icalduration.h
@@ -45,7 +45,7 @@ struct icaldurationtype icaldurationtype_from_int(int t);
 struct icaldurationtype icaldurationtype_from_string(const char*);
 int icaldurationtype_as_int(struct icaldurationtype duration);
 char* icaldurationtype_as_ical_string(struct icaldurationtype d);
-struct icaldurationtype icaldurationtype_null_duration();
+struct icaldurationtype icaldurationtype_null_duration(void);
 int icaldurationtype_is_null_duration(struct icaldurationtype d);
 
 struct icaltimetype  icaltime_add(struct icaltimetype t,
diff --git a/libical/src/libical/icalvalue.c b/libical/src/libical/icalvalue.c
index 7414c7c173..b7852c3216 100644
--- a/libical/src/libical/icalvalue.c
+++ b/libical/src/libical/icalvalue.c
@@ -436,12 +436,11 @@ icalvalue_new_from_string_with_error(icalvalue_kind kind,const char* str,icalpro
         case ICAL_DURATION_VALUE:
 	{
             struct icaldurationtype dur = icaldurationtype_from_string(str);
-            
-            if(icaldurationtype_is_null_duration(dur)){
-                value = 0;
-            } else {
+
+	    if (icalerrno == ICAL_MALFORMEDDATA_ERROR)
+		value = 0;
+	    else
                 value = icalvalue_new_duration(dur);
-            }
 
 	    break;
 	}