diff --git a/cl/class.go b/cl/class.go
index f1338e961..4b9ece9ff 100644
--- a/cl/class.go
+++ b/cl/class.go
@@ -251,6 +251,15 @@ func initClassTypeEx(ctx *pkgCtx, typDecl typDecl, this *classCtx, goName string
 	if *feats&featAllIgnore != 0 {
 		return
 	}
+	// A record that holds a callback (function pointer) field must carry the
+	// "// llgo:type C" directive so those callbacks use the C calling
+	// convention, mirroring how function-pointer typedefs are handled (see
+	// defineTypedef). featHasCallback is set by toTypeEx while visiting the
+	// members above, so it is only known now; upgrade the doc-only comment set
+	// at the top of this function to the directive form.
+	if *feats&featHasCallback != 0 {
+		typDecl.defs.SetComments(ctx.directiveTypeC(cls, true))
+	}
 	// Establish the layout at offset 0, following the C++ Itanium ABI. A
 	// polymorphic class shares its vptr with its primary base (the first
 	// non-virtual *polymorphic* direct base in declaration order); that base is
diff --git a/tool/_testc/clang-c-22.1.8/Index.go b/tool/_testc/clang-c-22.1.8/Index.go
index 0755834d8..bb913e91c 100644
--- a/tool/_testc/clang-c-22.1.8/Index.go
+++ b/tool/_testc/clang-c-22.1.8/Index.go
@@ -2470,6 +2470,8 @@ type InclusionVisitor = func(_llcppg_param1 File, _llcppg_param2 *SourceLocation
 
 // Evaluation result of a cursor
 type EvalResult uintptr
+
+// llgo:type C
 type CursorAndRangeVisitor struct {
 	Context unsafe.Pointer
 	Visit   func(_llcppg_param1 unsafe.Pointer, _llcppg_param2 Cursor, _llcppg_param3 SourceRange) VisitorResult
@@ -2605,6 +2607,8 @@ type IdxEntityRefInfo struct {
 
 // A group of callbacks used by #clang_indexSourceFile and
 // #clang_indexTranslationUnit.
+//
+// llgo:type C
 type IndexerCallbacks struct {
 	AbortQuery             func(_llcppg_param1 ClientData, _llcppg_param2 unsafe.Pointer) c.Int
 	Diagnostic             func(_llcppg_param1 ClientData, _llcppg_param2 DiagnosticSet, _llcppg_param3 unsafe.Pointer)
diff --git a/tool/_testc/clang-c-22.1.8/Index/out.go b/tool/_testc/clang-c-22.1.8/Index/out.go
index a13eab4ae..24484d70d 100644
--- a/tool/_testc/clang-c-22.1.8/Index/out.go
+++ b/tool/_testc/clang-c-22.1.8/Index/out.go
@@ -2644,6 +2644,8 @@ type InclusionVisitor = func(_llcppg_param1 CXFile.File, _llcppg_param2 *CXSourc
 
 // Evaluation result of a cursor
 type EvalResult uintptr
+
+// llgo:type C
 type CursorAndRangeVisitor struct {
 	Context unsafe.Pointer
 	Visit   func(_llcppg_param1 unsafe.Pointer, _llcppg_param2 Cursor, _llcppg_param3 CXSourceLocation.SourceRange) VisitorResult
@@ -2779,6 +2781,8 @@ type IdxEntityRefInfo struct {
 
 // A group of callbacks used by #clang_indexSourceFile and
 // #clang_indexTranslationUnit.
+//
+// llgo:type C
 type IndexerCallbacks struct {
 	AbortQuery             func(_llcppg_param1 ClientData, _llcppg_param2 unsafe.Pointer) c.Int
 	Diagnostic             func(_llcppg_param1 ClientData, _llcppg_param2 CXDiagnostic.DiagnosticSet, _llcppg_param3 unsafe.Pointer)
diff --git a/tool/_testc/python-3.14.8/pythread.go b/tool/_testc/python-3.14.8/pythread.go
index fb2b53eeb..59c341b2f 100644
--- a/tool/_testc/python-3.14.8/pythread.go
+++ b/tool/_testc/python-3.14.8/pythread.go
@@ -42,6 +42,8 @@ type TssT = X_tssT
 type X_object struct {
 }
 type Object = X_object
+
+// llgo:type C
 type MemAllocatorEx struct {
 	Ctx     unsafe.Pointer
 	Malloc  func(_llcppg_param1 unsafe.Pointer, _llcppg_param2 c.SizeT) unsafe.Pointer