@@ -10,6 +10,8 @@ Supported Python versions:
 * Python 3.6 - 3.16
 * PyPy 3.6 - 3.12
 
+The limited C API is only supported on CPython.
+
 A C11 subset (without optional features) is required, like ``static inline``
 functions: see `PEP 7 <https://www.python.org/dev/peps/pep-0007/>`_.
 
 
@@ -0,0 +1,77 @@
+// C extension made of two C files (extension.c and static_inline.c) to detect
+// when a pythoncapi_compat.h function is implemented without "static inline".
+
+#ifndef MODULE_NAME
+#   error "MODULE_NAME macro is not set"
+#endif
+
+#include "pythoncapi_compat.h"
+
+#define _STR(NAME) #NAME
+#define STR(NAME) _STR(NAME)
+#define _CONCAT(a, b) a ## b
+#define CONCAT(a, b) _CONCAT(a, b)
+
+
+// No method and no module exec method needed, most basic C extension
+
+
+// Use PySlot API on Python 3.15 and newer and on limited C API 3.15 and newer
+#if (PY_VERSION_HEX >= _Py_PACK_VERSION(3, 15) \
+     && (!defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= _Py_PACK_VERSION(3, 15)))
+
+PyABIInfo_VAR(abi_info);
+
+static PySlot module_slots[] = {
+    PySlot_PTR_STATIC(Py_mod_abi, &abi_info),
+    PySlot_PTR_STATIC(Py_mod_name, (void*)STR(MODULE_NAME)),
+    PySlot_PTR_STATIC(Py_mod_state_size, 0),
+    PySlot_PTR_STATIC(Py_mod_gil, Py_MOD_GIL_NOT_USED),
+    {0, 0, {0}, {0}}
+};
+
+#define EXPORT_FUNC CONCAT(PyModExport_, MODULE_NAME)
+
+PyMODEXPORT_FUNC
+EXPORT_FUNC(void)
+{
+    return module_slots;
+}
+
+#ifdef MS_WINDOWS
+#   define INIT_FUNC CONCAT(PyInit_, MODULE_NAME)
+
+// Workaround for https://github.com/pypa/distutils/issues/387
+// https://docs.python.org/3.16/howto/abi3t-migration.html#module-export-hook
+PyMODINIT_FUNC
+INIT_FUNC(void)
+{
+    PyErr_SetString(PyExc_SystemError,
+                    "PyInit_* called for module with PyModExport_*");
+    return NULL;
+}
+#endif
+
+#else
+
+static struct PyModuleDef module_def = {
+    PyModuleDef_HEAD_INIT,
+    STR(MODULE_NAME),    // m_name
+    _Py_NULL,            // m_doc
+    0,                   // m_size
+    _Py_NULL,            // m_methods
+    _Py_NULL,            // m_slots
+    _Py_NULL,            // m_traverse
+    _Py_NULL,            // m_clear
+    _Py_NULL,            // m_free
+};
+
+
+#define INIT_FUNC CONCAT(PyInit_, MODULE_NAME)
+
+PyMODINIT_FUNC
+INIT_FUNC(void)
+{
+    return PyModule_Create(&module_def);
+}
+#endif
@@ -202,6 +202,28 @@ def add_common_flags(flags, limited):
             language='c++')
         extensions.append(ext)
 
+    # Build a C extension with two C files to detect when a pythoncapi_compat.h
+    # function is implemented without "static inline".
+    sources = [
+        'extension.c',
+        'static_inline.c',
+    ]
+    for limited in (False, True):
+        if limited and not TEST_LIMITED_C_API:
+            continue
+        name = 'test_pythoncapi_compat_ext'
+        assert name != C_EXTENSION_PREFIX
+        flags = list(COMMON_FLAGS)
+        if limited:
+            name += LIMITED_SUFFIX
+            flags.append(limited_flag)
+        flags.append(f'-DMODULE_NAME={name}')
+        ext = Extension(
+            name,
+            sources=sources,
+            extra_compile_args=flags)
+        extensions.append(ext)
+
     setup(name="test_pythoncapi_compat", ext_modules=extensions)
 
 
 
@@ -0,0 +1,6 @@
+// C extension made of two C files (extension.c and static_inline.c) to detect
+// when a pythoncapi_compat.h function is implemented without "static inline".
+
+#include "pythoncapi_compat.h"
+
+// No function defined, only #include "pythoncapi_compat.h"
@@ -1,17 +1,17 @@
 // Always enable assertions
 #undef NDEBUG
 
+#ifndef MODULE_NAME
+#   error "MODULE_NAME macro is not set"
+#endif
+
 #include "pythoncapi_compat.h"
 #include <structmember.h>   // T_SHORT, READONLY
 
 #ifdef NDEBUG
 #   error "assertions must be enabled"
 #endif
 
-#ifndef MODULE_NAME
-#   error "MODULE_NAME macro is not set"
-#endif
-
 #define _STR(NAME) #NAME
 #define STR(NAME) _STR(NAME)
 #define _CONCAT(a, b) a ## b