diff --git a/src/FilenamesIterator.zig b/src/FilenamesIterator.zig
index c46e847..c8afc06 100644
--- a/src/FilenamesIterator.zig
+++ b/src/FilenamesIterator.zig
@@ -16,11 +16,9 @@ filenames: ?*c.notmuch_filenames_t,
 /// identical to it (and the object to which it ultimately belongs).
 pub fn next(self: *FilenamesIterator) ?[:0]const u8 {
     const filenames = self.filenames orelse return null;
-    if (c.notmuch_threads_valid(filenames) != 0) return null;
-    defer c.notmuch_threads_move_to_next(filenames);
-    return .{
-        .thread = std.mem.span(c.notmuch_threads_get(filenames) orelse unreachable),
-    };
+    if (c.notmuch_filenames_valid(filenames) == 0) return null;
+    defer c.notmuch_filenames_move_to_next(filenames);
+    return std.mem.span(c.notmuch_filenames_get(filenames) orelse unreachable);
 }
 
 /// Deinitialize a `FilenamesIterator` object.
diff --git a/src/MessagesIterator.zig b/src/MessagesIterator.zig
index 514a221..2deac45 100644
--- a/src/MessagesIterator.zig
+++ b/src/MessagesIterator.zig
@@ -40,9 +40,9 @@ pub fn collectTags(self: *const MessagesIterator) ?TagsIterator {
 
 pub fn next(self: *const MessagesIterator) NextError!?Message {
     const messages = self.messages orelse return null;
-    return switch (status(c.notmuch_threads_status(messages))) {
+    return switch (status(c.notmuch_messages_status(messages))) {
         .success => message: {
-            if (c.notmuch_messages_valid(messages) != 0) break :message null;
+            if (c.notmuch_messages_valid(messages) == 0) break :message null;
             defer c.notmuch_messages_move_to_next(messages);
             break :message .{
                 .message = c.notmuch_messages_get(messages) orelse unreachable,
diff --git a/src/ThreadsIterator.zig b/src/ThreadsIterator.zig
index 8a52219..1a49153 100644
--- a/src/ThreadsIterator.zig
+++ b/src/ThreadsIterator.zig
@@ -24,7 +24,7 @@ pub fn next(self: *ThreadsIterator) NextError!?Thread {
     const threads = self.threads orelse return null;
     return switch (status(c.notmuch_threads_status(threads))) {
         .success => thread: {
-            if (c.notmuch_threads_valid(threads) != 0) break :thread null;
+            if (c.notmuch_threads_valid(threads) == 0) break :thread null;
             defer c.notmuch_threads_move_to_next(threads);
             break :thread .{
                 .thread = c.notmuch_threads_get(threads) orelse unreachable,