diff --git a/cl/_testrt/qsortfn/in.go b/cl/_testrt/qsortfn/in.go
new file mode 100644
index 00000000..fb527a04
--- /dev/null
+++ b/cl/_testrt/qsortfn/in.go
@@ -0,0 +1,150 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+	q "github.com/goplus/llgo/cl/internal/qsort"
+)
+
+// llgo:type C
+type Comp func(a, b c.Pointer) c.Int
+
+//go:linkname qsort C.qsort
+func qsort(base c.Pointer, count, elem uintptr, compar Comp)
+
+//go:linkname qsort2 C.qsort
+func qsort2(base c.Pointer, count, elem uintptr, compar func(a, b c.Pointer) c.Int)
+
+func main() {
+	sort1a()
+	sort1b()
+	sort2a()
+	sort2b()
+	sort3a()
+	sort3b()
+	sort4a()
+	sort4b()
+	sort5a()
+	sort5b()
+}
+
+func sort1a() {
+	c.Printf(c.Str("Comp => Comp\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort1b() {
+	c.Printf(c.Str("fn => Comp\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort2a() {
+	c.Printf(c.Str("Comp => fn\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	qsort2(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort2b() {
+	c.Printf(c.Str("fn => fn\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	qsort2(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort3a() {
+	c.Printf(c.Str("qsort.Comp => qsort.Comp\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn q.Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	q.Qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort3b() {
+	c.Printf(c.Str("fn => qsort.Comp\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	q.Qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort4a() {
+	c.Printf(c.Str("qsort.Comp => fn\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn q.Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	qsort2(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort4b() {
+	c.Printf(c.Str("Comp => qsort.fn\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	q.Qsort2(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), fn)
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort5a() {
+	c.Printf(c.Str("qsort.Comp => Comp()\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn q.Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), Comp(fn))
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
+
+func sort5b() {
+	c.Printf(c.Str("Comp => qsort.Comp()\n"))
+	a := [...]int{100, 8, 23, 2, 7}
+	var fn Comp = func(a, b c.Pointer) c.Int {
+		return c.Int(*(*int)(a) - *(*int)(b))
+	}
+	q.Qsort(c.Pointer(&a[0]), 5, unsafe.Sizeof(0), q.Comp(fn))
+	for _, v := range a {
+		c.Printf(c.Str("%d\n"), v)
+	}
+}
diff --git a/cl/_testrt/qsortfn/out.ll b/cl/_testrt/qsortfn/out.ll
new file mode 100644
index 00000000..50d3b69e
--- /dev/null
+++ b/cl/_testrt/qsortfn/out.ll
@@ -0,0 +1,596 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+@"main.init$guard" = global i1 false, align 1
+@__llgo_argc = global i32 0, align 4
+@__llgo_argv = global ptr null, align 8
+@0 = private unnamed_addr constant [14 x i8] c"Comp => Comp\0A\00", align 1
+@1 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@2 = private unnamed_addr constant [12 x i8] c"fn => Comp\0A\00", align 1
+@3 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@4 = private unnamed_addr constant [12 x i8] c"Comp => fn\0A\00", align 1
+@5 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@6 = private unnamed_addr constant [10 x i8] c"fn => fn\0A\00", align 1
+@7 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@8 = private unnamed_addr constant [26 x i8] c"qsort.Comp => qsort.Comp\0A\00", align 1
+@9 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@10 = private unnamed_addr constant [18 x i8] c"fn => qsort.Comp\0A\00", align 1
+@11 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@12 = private unnamed_addr constant [18 x i8] c"qsort.Comp => fn\0A\00", align 1
+@13 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@14 = private unnamed_addr constant [18 x i8] c"Comp => qsort.fn\0A\00", align 1
+@15 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@16 = private unnamed_addr constant [22 x i8] c"qsort.Comp => Comp()\0A\00", align 1
+@17 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+@18 = private unnamed_addr constant [22 x i8] c"Comp => qsort.Comp()\0A\00", align 1
+@19 = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define i32 @main(i32 %0, ptr %1) {
+_llgo_0:
+  store i32 %0, ptr @__llgo_argc, align 4
+  store ptr %1, ptr @__llgo_argv, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  call void @main.sort1a()
+  call void @main.sort1b()
+  call void @main.sort2a()
+  call void @main.sort2b()
+  call void @main.sort3a()
+  call void @main.sort3b()
+  call void @main.sort4a()
+  call void @main.sort4b()
+  call void @main.sort5a()
+  call void @main.sort5b()
+  ret i32 0
+}
+
+define void @main.sort1a() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @0)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %7, i64 5, i64 8, ptr @"main.sort1a$1")
+  %8 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %9 = phi i64 [ -1, %_llgo_0 ], [ %10, %_llgo_2 ]
+  %10 = add i64 %9, 1
+  %11 = icmp slt i64 %10, 5
+  br i1 %11, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %12 = icmp slt i64 %10, 0
+  %13 = icmp sge i64 %10, 5
+  %14 = or i1 %13, %12
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %14)
+  %15 = getelementptr inbounds i64, ptr %1, i64 %10
+  %16 = load i64, ptr %15, align 4
+  %17 = call i32 (ptr, ...) @printf(ptr @1, i64 %16)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort1a$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort1b() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @2)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %7, i64 5, i64 8, ptr @"main.sort1b$1")
+  %8 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %9 = phi i64 [ -1, %_llgo_0 ], [ %10, %_llgo_2 ]
+  %10 = add i64 %9, 1
+  %11 = icmp slt i64 %10, 5
+  br i1 %11, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %12 = icmp slt i64 %10, 0
+  %13 = icmp sge i64 %10, 5
+  %14 = or i1 %13, %12
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %14)
+  %15 = getelementptr inbounds i64, ptr %1, i64 %10
+  %16 = load i64, ptr %15, align 4
+  %17 = call i32 (ptr, ...) @printf(ptr @3, i64 %16)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort1b$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort2a() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @4)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %7, i64 5, i64 8, ptr @"main.sort2a$1")
+  %8 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %9 = phi i64 [ -1, %_llgo_0 ], [ %10, %_llgo_2 ]
+  %10 = add i64 %9, 1
+  %11 = icmp slt i64 %10, 5
+  br i1 %11, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %12 = icmp slt i64 %10, 0
+  %13 = icmp sge i64 %10, 5
+  %14 = or i1 %13, %12
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %14)
+  %15 = getelementptr inbounds i64, ptr %1, i64 %10
+  %16 = load i64, ptr %15, align 4
+  %17 = call i32 (ptr, ...) @printf(ptr @5, i64 %16)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort2a$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort2b() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @6)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %7, i64 5, i64 8, ptr @"main.sort2b$1")
+  %8 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %9 = phi i64 [ -1, %_llgo_0 ], [ %10, %_llgo_2 ]
+  %10 = add i64 %9, 1
+  %11 = icmp slt i64 %10, 5
+  br i1 %11, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %12 = icmp slt i64 %10, 0
+  %13 = icmp sge i64 %10, 5
+  %14 = or i1 %13, %12
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %14)
+  %15 = getelementptr inbounds i64, ptr %1, i64 %10
+  %16 = load i64, ptr %15, align 4
+  %17 = call i32 (ptr, ...) @printf(ptr @7, i64 %16)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort2b$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort3a() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @8)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = alloca { ptr, ptr }, align 8
+  %8 = getelementptr inbounds { ptr, ptr }, ptr %7, i32 0, i32 0
+  store ptr @"__llgo_stub.main.sort3a$1", ptr %8, align 8
+  %9 = getelementptr inbounds { ptr, ptr }, ptr %7, i32 0, i32 1
+  store ptr null, ptr %9, align 8
+  %10 = load { ptr, ptr }, ptr %7, align 8
+  %11 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %11, i64 5, i64 8, { ptr, ptr } %10)
+  %12 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %13 = phi i64 [ -1, %_llgo_0 ], [ %14, %_llgo_2 ]
+  %14 = add i64 %13, 1
+  %15 = icmp slt i64 %14, 5
+  br i1 %15, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %16 = icmp slt i64 %14, 0
+  %17 = icmp sge i64 %14, 5
+  %18 = or i1 %17, %16
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %18)
+  %19 = getelementptr inbounds i64, ptr %1, i64 %14
+  %20 = load i64, ptr %19, align 4
+  %21 = call i32 (ptr, ...) @printf(ptr @9, i64 %20)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort3a$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort3b() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @10)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  %8 = alloca { ptr, ptr }, align 8
+  %9 = getelementptr inbounds { ptr, ptr }, ptr %8, i32 0, i32 0
+  store ptr @"__llgo_stub.main.sort3b$1", ptr %9, align 8
+  %10 = getelementptr inbounds { ptr, ptr }, ptr %8, i32 0, i32 1
+  store ptr null, ptr %10, align 8
+  %11 = load { ptr, ptr }, ptr %8, align 8
+  call void @qsort(ptr %7, i64 5, i64 8, { ptr, ptr } %11)
+  %12 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %13 = phi i64 [ -1, %_llgo_0 ], [ %14, %_llgo_2 ]
+  %14 = add i64 %13, 1
+  %15 = icmp slt i64 %14, 5
+  br i1 %15, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %16 = icmp slt i64 %14, 0
+  %17 = icmp sge i64 %14, 5
+  %18 = or i1 %17, %16
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %18)
+  %19 = getelementptr inbounds i64, ptr %1, i64 %14
+  %20 = load i64, ptr %19, align 4
+  %21 = call i32 (ptr, ...) @printf(ptr @11, i64 %20)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort3b$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort4a() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @12)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = alloca { ptr, ptr }, align 8
+  %8 = getelementptr inbounds { ptr, ptr }, ptr %7, i32 0, i32 0
+  store ptr @"__llgo_stub.main.sort4a$1", ptr %8, align 8
+  %9 = getelementptr inbounds { ptr, ptr }, ptr %7, i32 0, i32 1
+  store ptr null, ptr %9, align 8
+  %10 = load { ptr, ptr }, ptr %7, align 8
+  %11 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %11, i64 5, i64 8, { ptr, ptr } %10)
+  %12 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %13 = phi i64 [ -1, %_llgo_0 ], [ %14, %_llgo_2 ]
+  %14 = add i64 %13, 1
+  %15 = icmp slt i64 %14, 5
+  br i1 %15, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %16 = icmp slt i64 %14, 0
+  %17 = icmp sge i64 %14, 5
+  %18 = or i1 %17, %16
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %18)
+  %19 = getelementptr inbounds i64, ptr %1, i64 %14
+  %20 = load i64, ptr %19, align 4
+  %21 = call i32 (ptr, ...) @printf(ptr @13, i64 %20)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort4a$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort4b() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @14)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %7, i64 5, i64 8, ptr @"main.sort4b$1")
+  %8 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %9 = phi i64 [ -1, %_llgo_0 ], [ %10, %_llgo_2 ]
+  %10 = add i64 %9, 1
+  %11 = icmp slt i64 %10, 5
+  br i1 %11, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %12 = icmp slt i64 %10, 0
+  %13 = icmp sge i64 %10, 5
+  %14 = or i1 %13, %12
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %14)
+  %15 = getelementptr inbounds i64, ptr %1, i64 %10
+  %16 = load i64, ptr %15, align 4
+  %17 = call i32 (ptr, ...) @printf(ptr @15, i64 %16)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort4b$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort5a() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @16)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = alloca { ptr, ptr }, align 8
+  %8 = getelementptr inbounds { ptr, ptr }, ptr %7, i32 0, i32 0
+  store ptr @"__llgo_stub.main.sort5a$1", ptr %8, align 8
+  %9 = getelementptr inbounds { ptr, ptr }, ptr %7, i32 0, i32 1
+  store ptr null, ptr %9, align 8
+  %10 = load { ptr, ptr }, ptr %7, align 8
+  %11 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %11, i64 5, i64 8, { ptr, ptr } %10)
+  %12 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %13 = phi i64 [ -1, %_llgo_0 ], [ %14, %_llgo_2 ]
+  %14 = add i64 %13, 1
+  %15 = icmp slt i64 %14, 5
+  br i1 %15, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %16 = icmp slt i64 %14, 0
+  %17 = icmp sge i64 %14, 5
+  %18 = or i1 %17, %16
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %18)
+  %19 = getelementptr inbounds i64, ptr %1, i64 %14
+  %20 = load i64, ptr %19, align 4
+  %21 = call i32 (ptr, ...) @printf(ptr @17, i64 %20)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort5a$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+define void @main.sort5b() {
+_llgo_0:
+  %0 = call i32 (ptr, ...) @printf(ptr @18)
+  %1 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 40)
+  %2 = getelementptr inbounds i64, ptr %1, i64 0
+  %3 = getelementptr inbounds i64, ptr %1, i64 1
+  %4 = getelementptr inbounds i64, ptr %1, i64 2
+  %5 = getelementptr inbounds i64, ptr %1, i64 3
+  %6 = getelementptr inbounds i64, ptr %1, i64 4
+  store i64 100, ptr %2, align 4
+  store i64 8, ptr %3, align 4
+  store i64 23, ptr %4, align 4
+  store i64 2, ptr %5, align 4
+  store i64 7, ptr %6, align 4
+  %7 = getelementptr inbounds i64, ptr %1, i64 0
+  call void @qsort(ptr %7, i64 5, i64 8, ptr @"main.sort5b$1")
+  %8 = load [5 x i64], ptr %1, align 4
+  br label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_2, %_llgo_0
+  %9 = phi i64 [ -1, %_llgo_0 ], [ %10, %_llgo_2 ]
+  %10 = add i64 %9, 1
+  %11 = icmp slt i64 %10, 5
+  br i1 %11, label %_llgo_2, label %_llgo_3
+
+_llgo_2:                                          ; preds = %_llgo_1
+  %12 = icmp slt i64 %10, 0
+  %13 = icmp sge i64 %10, 5
+  %14 = or i1 %13, %12
+  call void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1 %14)
+  %15 = getelementptr inbounds i64, ptr %1, i64 %10
+  %16 = load i64, ptr %15, align 4
+  %17 = call i32 (ptr, ...) @printf(ptr @19, i64 %16)
+  br label %_llgo_1
+
+_llgo_3:                                          ; preds = %_llgo_1
+  ret void
+}
+
+define i32 @"main.sort5b$1"(ptr %0, ptr %1) {
+_llgo_0:
+  %2 = load i64, ptr %0, align 4
+  %3 = load i64, ptr %1, align 4
+  %4 = sub i64 %2, %3
+  %5 = trunc i64 %4 to i32
+  ret i32 %5
+}
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare i32 @printf(ptr, ...)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
+
+declare void @qsort(ptr, i64, i64, ptr)
+
+declare void @"github.com/goplus/llgo/internal/runtime.AssertIndexRange"(i1)
+
+define linkonce i32 @"__llgo_stub.main.sort3a$1"(ptr %0, ptr %1, ptr %2) {
+_llgo_0:
+  %3 = tail call i32 @"main.sort3a$1"(ptr %1, ptr %2)
+  ret i32 %3
+}
+
+define linkonce i32 @"__llgo_stub.main.sort3b$1"(ptr %0, ptr %1, ptr %2) {
+_llgo_0:
+  %3 = tail call i32 @"main.sort3b$1"(ptr %1, ptr %2)
+  ret i32 %3
+}
+
+define linkonce i32 @"__llgo_stub.main.sort4a$1"(ptr %0, ptr %1, ptr %2) {
+_llgo_0:
+  %3 = tail call i32 @"main.sort4a$1"(ptr %1, ptr %2)
+  ret i32 %3
+}
+
+define linkonce i32 @"__llgo_stub.main.sort5a$1"(ptr %0, ptr %1, ptr %2) {
+_llgo_0:
+  %3 = tail call i32 @"main.sort5a$1"(ptr %1, ptr %2)
+  ret i32 %3
+}
diff --git a/cl/import.go b/cl/import.go
index 36597b28..aa09ba60 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -196,6 +196,15 @@ func (p *context) initFiles(pkgPath string, files []*ast.File) {
 							p.collectSkipNames(line)
 						}
 					}
+				case token.TYPE:
+					if len(decl.Specs) == 1 {
+						if hasTypec(decl.Doc) {
+							inPkgName := decl.Specs[0].(*ast.TypeSpec).Name.Name
+							if obj := p.goTyps.Scope().Lookup(inPkgName); obj != nil {
+								p.prog.Type(obj.Type(), llssa.InC)
+							}
+						}
+					}
 				}
 			}
 		}
@@ -544,4 +553,43 @@ func (p *context) initPyModule() {
 	}
 }
 
+// ParsePkgSyntax: check llgo:type C
+func ParsePkgSyntax(prog llssa.Program, pkg *types.Package, files []*ast.File) {
+	for _, file := range files {
+		for _, decl := range file.Decls {
+			switch decl := decl.(type) {
+			case *ast.GenDecl:
+				switch decl.Tok {
+				case token.TYPE:
+					if len(decl.Specs) == 1 {
+						if hasTypec(decl.Doc) {
+							inPkgName := decl.Specs[0].(*ast.TypeSpec).Name.Name
+							if obj := pkg.Scope().Lookup(inPkgName); obj != nil {
+								prog.Type(obj.Type(), llssa.InC)
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+const (
+	llgotypec  = "//llgo:type C"
+	llgotypec2 = "// llgo:type C"
+)
+
+func hasTypec(doc *ast.CommentGroup) bool {
+	if doc != nil {
+		if n := len(doc.List); n > 0 {
+			line := doc.List[n-1].Text
+			if strings.HasPrefix(line, llgotypec) || strings.HasPrefix(line, llgotypec2) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // -----------------------------------------------------------------------------
diff --git a/cl/internal/qsort/qsort.go b/cl/internal/qsort/qsort.go
new file mode 100644
index 00000000..394066ce
--- /dev/null
+++ b/cl/internal/qsort/qsort.go
@@ -0,0 +1,20 @@
+package qsort
+
+import (
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+const (
+	LLGoPackage = "decl"
+)
+
+// llgo:type C
+type Comp func(a, b c.Pointer) c.Int
+
+//go:linkname Qsort C.qsort
+func Qsort(base c.Pointer, count, elem uintptr, compar Comp)
+
+//go:linkname Qsort2 C.qsort
+func Qsort2(base c.Pointer, count, elem uintptr, compar func(a, b c.Pointer) c.Int)
diff --git a/internal/build/build.go b/internal/build/build.go
index 3d2d5241..0b06e549 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -247,10 +247,12 @@ func buildAllPkgs(ctx *context, initial []*packages.Package, verbose bool) (pkgs
 			continue
 		}
 		built[pkg.PkgPath] = none{}
+		//parsePkg(ctx, aPkg, verbose)
 		switch kind, param := cl.PkgKindOf(pkg.Types); kind {
 		case cl.PkgDeclOnly:
 			// skip packages that only contain declarations
 			// and set no export file
+			cl.ParsePkgSyntax(ctx.prog, pkg.Types, pkg.Syntax)
 			pkg.ExportFile = ""
 		case cl.PkgLinkIR, cl.PkgLinkExtern, cl.PkgPyModule:
 			if isPkgInLLGo(pkg.PkgPath) {
@@ -427,6 +429,7 @@ func buildPkg(ctx *context, aPkg *aPackage, verbose bool) {
 		llssa.SetDebug(llssa.DbgFlagAll)
 		cl.SetDebug(cl.DbgFlagAll)
 	}
+
 	ret, err := cl.NewPackageEx(ctx.prog, ctx.patches, aPkg.SSA, syntax)
 	if showDetail {
 		llssa.SetDebug(0)
diff --git a/ssa/expr.go b/ssa/expr.go
index 2aed82c3..bf9d8e0b 100644
--- a/ssa/expr.go
+++ b/ssa/expr.go
@@ -704,11 +704,9 @@ func (b Builder) ChangeType(t Type, x Expr) (ret Expr) {
 	if debugInstr {
 		log.Printf("ChangeType %v, %v\n", t.RawType(), x.impl)
 	}
-	typ := t.raw.Type
-	switch t.kind {
-	case vkClosure:
-		ret.impl = checkExpr(x, typ.Underlying(), b).impl
-	default:
+	if t.kind == vkClosure && x.kind == vkFuncDecl {
+		ret.impl = checkExpr(x, t.raw.Type.Underlying(), b).impl
+	} else {
 		ret.impl = x.impl
 	}
 	ret.Type = t
@@ -946,7 +944,7 @@ func (b Builder) Call(fn Expr, args ...Expr) (ret Expr) {
 		raw = fn.raw.Type
 		fallthrough
 	case vkFuncPtr:
-		sig = raw.(*types.Signature)
+		sig = raw.Underlying().(*types.Signature)
 		ll = b.Prog.FuncDecl(sig, InC).ll
 	case vkFuncDecl:
 		sig = raw.(*types.Signature)