diff --git a/src/common/chunkedvector.c b/src/common/chunkedvector.c
index f965c32b..b60c8404 100644
--- a/src/common/chunkedvector.c
+++ b/src/common/chunkedvector.c
@@ -6,7 +6,7 @@
 #include <intrin.h>
 #endif
 
-PK_INLINE int c11__bit_length(unsigned long x) {
+extern PK_INLINE int c11__bit_length(unsigned long x) {
 #if(defined(__clang__) || defined(__GNUC__))
     return x == 0 ? 0 : (int)sizeof(unsigned long) * 8 - __builtin_clzl(x);
 #elif defined(_MSC_VER)
diff --git a/src/interpreter/typeinfo.c b/src/interpreter/typeinfo.c
index a20b76ce..bb24245a 100644
--- a/src/interpreter/typeinfo.c
+++ b/src/interpreter/typeinfo.c
@@ -11,7 +11,7 @@ py_ItemRef pk_tpfindname(py_TypeInfo* ti, py_Name name) {
     return NULL;
 }
 
-PK_INLINE py_TypeInfo* pk_typeinfo(py_Type type) {
+extern PK_INLINE py_TypeInfo* pk_typeinfo(py_Type type) {
 #ifndef NDEBUG
     int length = pk_current_vm->types.length;
     if(type <= 0 || type >= length) {
diff --git a/src/objects/object.c b/src/objects/object.c
index 1a3f7ef4..3625910d 100644
--- a/src/objects/object.c
+++ b/src/objects/object.c
@@ -2,16 +2,16 @@
 #include "pocketpy/pocketpy.h"
 #include <assert.h>
 
-PK_INLINE void* PyObject__userdata(PyObject* self) {
+extern PK_INLINE void* PyObject__userdata(PyObject* self) {
     return self->flex + PK_OBJ_SLOTS_SIZE(self->slots);
 }
 
-PK_INLINE NameDict* PyObject__dict(PyObject* self) {
+extern PK_INLINE NameDict* PyObject__dict(PyObject* self) {
     assert(self->slots == -1);
     return (NameDict*)(self->flex);
 }
 
-PK_INLINE py_TValue* PyObject__slots(PyObject* self) {
+extern PK_INLINE py_TValue* PyObject__slots(PyObject* self) {
     assert(self->slots >= 0);
     return (py_TValue*)(self->flex);
 }
\ No newline at end of file