numpy · charris · Jan 17, 2022 · Jan 13, 2022 · Jan 13, 2022 · Jan 14, 2022
diff --git a/numpy/core/include/numpy/ufuncobject.h b/numpy/core/include/numpy/ufuncobject.h
@@ -173,7 +173,11 @@ typedef struct _tagPyUFuncObject {
          * but this was never implemented. (This is also why the above
          * selector is called the "legacy" selector.)
          */
-        vectorcallfunc vectorcall;
+        #ifndef Py_LIMITED_API
+            vectorcallfunc vectorcall;
+        #else
+            void *vectorcall;
+        #endif
 
         /* Was previously the `PyUFunc_MaskedInnerLoopSelectionFunc` */
         void *_always_null_previously_masked_innerloop_selector;

diff --git a/numpy/core/tests/examples/checks.pyx → numpy/core/tests/examples/cython/checks.pyx b/numpy/core/tests/examples/checks.pyx → numpy/core/tests/examples/cython/checks.pyx
diff --git a/numpy/core/tests/examples/setup.py → numpy/core/tests/examples/cython/setup.py b/numpy/core/tests/examples/setup.py → numpy/core/tests/examples/cython/setup.py
diff --git a/numpy/core/tests/examples/limited_api/limited_api.c b/numpy/core/tests/examples/limited_api/limited_api.c
@@ -0,0 +1,17 @@
+#define Py_LIMITED_API 0x03060000
+
+#include <Python.h>
+#include <numpy/arrayobject.h>
+#include <numpy/ufuncobject.h>
+
+static PyModuleDef moduledef = {
+    .m_base = PyModuleDef_HEAD_INIT,
+    .m_name = "limited_api"
+};
+
+PyMODINIT_FUNC PyInit_limited_api(void)
+{
+    import_array();
+    import_umath();
+    return PyModule_Create(&moduledef);
+}
diff --git a/numpy/core/tests/examples/limited_api/setup.py b/numpy/core/tests/examples/limited_api/setup.py
@@ -0,0 +1,22 @@
+"""
+Build an example package using the limited Python C API.
+"""
+
+import numpy as np
+from setuptools import setup, Extension
+import os
+
+macros = [("NPY_NO_DEPRECATED_API", 0), ("Py_LIMITED_API", "0x03060000")]
+
+limited_api = Extension(
+    "limited_api",
+    sources=[os.path.join('.', "limited_api.c")],
+    include_dirs=[np.get_include()],
+    define_macros=macros,
+)
+
+extensions = [limited_api]
+
+setup(
+    ext_modules=extensions
+)
diff --git a/numpy/core/tests/test_cython.py b/numpy/core/tests/test_cython.py
@@ -32,7 +32,7 @@ def install_temp(request, tmp_path):
     # Based in part on test_cython from random.tests.test_extending
 
     here = os.path.dirname(__file__)
-    ext_dir = os.path.join(here, "examples")
+    ext_dir = os.path.join(here, "examples", "cython")
 
     cytest = str(tmp_path / "cytest")
 

diff --git a/numpy/core/tests/test_limited_api.py b/numpy/core/tests/test_limited_api.py
@@ -0,0 +1,41 @@
+import os
+import shutil
+import subprocess
+import sys
+import sysconfig
+import pytest
+
+
+@pytest.mark.xfail(
+    sysconfig.get_config_var("Py_DEBUG"),
+    reason=(
+        "Py_LIMITED_API is incompatible with Py_DEBUG, Py_TRACE_REFS, "
+        "and Py_REF_DEBUG"
+    ),
+)
+def test_limited_api(tmp_path):
+    """Test building a third-party C extension with the limited API."""
+    # Based in part on test_cython from random.tests.test_extending
+
+    here = os.path.dirname(__file__)
+    ext_dir = os.path.join(here, "examples", "limited_api")
+
+    cytest = str(tmp_path / "limited_api")
+
+    shutil.copytree(ext_dir, cytest)
+    # build the examples and "install" them into a temporary directory
+
+    install_log = str(tmp_path / "tmp_install_log.txt")
+    subprocess.check_call(
+        [
+            sys.executable,
+            "setup.py",
+            "build",
+            "install",
+            "--prefix", str(tmp_path / "installdir"),
+            "--single-version-externally-managed",
+            "--record",
+            install_log,
+        ],
+        cwd=cytest,
+    )