diff --git a/deltachat-ffi/src/lib.rs b/deltachat-ffi/src/lib.rs
index cf0c36bcc..3e9ac76cb 100644
--- a/deltachat-ffi/src/lib.rs
+++ b/deltachat-ffi/src/lib.rs
@@ -1290,7 +1290,7 @@ pub unsafe extern "C" fn dc_msg_get_height(msg: *mut dc_msg::dc_msg_t) -> libc::
 
 #[no_mangle]
 pub unsafe extern "C" fn dc_msg_get_duration(msg: *mut dc_msg::dc_msg_t) -> libc::c_int {
-    dc_msg::dc_msg_get_duration(msg) as libc::c_int
+    dc_msg::dc_msg_get_duration(msg)
 }
 
 #[no_mangle]
diff --git a/src/dc_contact.rs b/src/dc_contact.rs
index ce812b844..9e5b0d25a 100644
--- a/src/dc_contact.rs
+++ b/src/dc_contact.rs
@@ -923,7 +923,7 @@ unsafe fn cat_fingerprint(
 pub unsafe fn dc_delete_contact(context: &dc_context_t, contact_id: uint32_t) -> bool {
     let mut success = false;
     let mut stmt: *mut sqlite3_stmt = 0 as *mut sqlite3_stmt;
-    if !contact_id <= 9i32 as libc::c_uint {
+    if !(contact_id <= 9i32 as libc::c_uint) {
         stmt = dc_sqlite3_prepare(
             context,
             &context.sql.clone().read().unwrap(),
diff --git a/src/dc_msg.rs b/src/dc_msg.rs
index 06cb7c196..786131fb9 100644
--- a/src/dc_msg.rs
+++ b/src/dc_msg.rs
@@ -903,12 +903,12 @@ pub unsafe fn dc_msg_get_height(msg: *const dc_msg_t) -> libc::c_int {
     dc_param_get_int((*msg).param, 'h' as i32, 0i32)
 }
 
-pub unsafe fn dc_msg_get_duration(msg: *const dc_msg_t) -> bool {
+pub unsafe fn dc_msg_get_duration(msg: *const dc_msg_t) -> libc::c_int {
     if msg.is_null() || (*msg).magic != 0x11561156i32 as libc::c_uint {
-        return false;
+        return 0;
     }
 
-    0 != dc_param_get_int((*msg).param, 'd' as i32, 0i32)
+    dc_param_get_int((*msg).param, 'd' as i32, 0i32)
 }
 
 // TODO should return bool /rtn