From 739abda8dec16c9f15ff283354dd43e960c6c2d1 Mon Sep 17 00:00:00 2001
From: Iain <iain1970@protonmail.com>
Date: Sun, 23 Aug 2026 00:15:08 +0100
Subject: [PATCH 1/2] purego: fix returning a C function pointer as a Go func

---
 func.go                     |  3 +--
 func_test.go                | 10 ++++++++++
 testdata/abitest/abi_test.c | 10 ++++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/func.go b/func.go
index 57afd93e..0da1dbc3 100644
--- a/func.go
+++ b/func.go
@@ -409,8 +409,7 @@ func RegisterFunc(fptr any, cfn uintptr) {
 			v = reflect.NewAt(outType, unsafe.Pointer(&a1)).Elem()
 		case reflect.Func:
 			// wrap this C function in a nicely typed Go function
-			v = reflect.New(outType)
-			RegisterFunc(v.Interface(), syscall.a1)
+			RegisterFunc(v.Addr().Interface(), syscall.a1)
 		case reflect.String:
 			v.SetString(strings.GoString(syscall.a1))
 		case reflect.Float32:
diff --git a/func_test.go b/func_test.go
index f5190714..6f31f04d 100644
--- a/func_test.go
+++ b/func_test.go
@@ -239,6 +239,16 @@ func TestABI(t *testing.T) {
 			t.Fatalf("%s: got %q, want %q", cName, res, want)
 		}
 	}
+	{
+		const cName = "return_func_ptr"
+		var fn func() func(a, b int32) int32
+		purego.RegisterLibFunc(&fn, lib, cName)
+		add := fn()
+		const expect = 5
+		if res := add(2, 3); res != expect {
+			t.Fatalf("%s: got %d, want %d", cName, res, expect)
+		}
+	}
 }
 
 func TestABI_ArgumentPassing(t *testing.T) {
diff --git a/testdata/abitest/abi_test.c b/testdata/abitest/abi_test.c
index c129d26d..4f187e25 100644
--- a/testdata/abitest/abi_test.c
+++ b/testdata/abitest/abi_test.c
@@ -197,3 +197,13 @@ double arm_float64_unaligned_on_stack(uintptr_t a1, uintptr_t a2, uintptr_t a3,
     return (double)a1 * 1 + (double)a2 * 2 + (double)a3 * 3 + (double)a4 * 4 +
            (double)a5 * 5 + a6;
 }
+
+typedef int32_t (*AddFunc)(int32_t, int32_t);
+
+int32_t returned_add(int32_t a, int32_t b) {
+    return a + b;
+}
+
+AddFunc return_func_ptr(void) {
+    return returned_add;
+}

From 2ae2a53c9fd6ed67d10e914d96f03d7a314e19f7 Mon Sep 17 00:00:00 2001
From: Iain <iain1970@protonmail.com>
Date: Sun, 23 Aug 2026 20:44:05 +0100
Subject: [PATCH 2/2] purego: keep a NULL C function pointer as a nil Go func

---
 func.go                     | 4 +++-
 func_test.go                | 8 ++++++++
 testdata/abitest/abi_test.c | 4 ++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/func.go b/func.go
index 0da1dbc3..005813be 100644
--- a/func.go
+++ b/func.go
@@ -409,7 +409,9 @@ func RegisterFunc(fptr any, cfn uintptr) {
 			v = reflect.NewAt(outType, unsafe.Pointer(&a1)).Elem()
 		case reflect.Func:
 			// wrap this C function in a nicely typed Go function
-			RegisterFunc(v.Addr().Interface(), syscall.a1)
+			if syscall.a1 != 0 {
+				RegisterFunc(v.Addr().Interface(), syscall.a1)
+			}
 		case reflect.String:
 			v.SetString(strings.GoString(syscall.a1))
 		case reflect.Float32:
diff --git a/func_test.go b/func_test.go
index 6f31f04d..fb853276 100644
--- a/func_test.go
+++ b/func_test.go
@@ -249,6 +249,14 @@ func TestABI(t *testing.T) {
 			t.Fatalf("%s: got %d, want %d", cName, res, expect)
 		}
 	}
+	{
+		const cName = "return_null_func_ptr"
+		var fn func() func(a, b int32) int32
+		purego.RegisterLibFunc(&fn, lib, cName)
+		if fn() != nil {
+			t.Fatalf("%s: got a non-nil func, want nil", cName)
+		}
+	}
 }
 
 func TestABI_ArgumentPassing(t *testing.T) {
diff --git a/testdata/abitest/abi_test.c b/testdata/abitest/abi_test.c
index 4f187e25..86eeca67 100644
--- a/testdata/abitest/abi_test.c
+++ b/testdata/abitest/abi_test.c
@@ -207,3 +207,7 @@ int32_t returned_add(int32_t a, int32_t b) {
 AddFunc return_func_ptr(void) {
     return returned_add;
 }
+
+AddFunc return_null_func_ptr(void) {
+    return NULL;
+}