Fix ufunc docstrings showing the C macro name

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [dev] - YYYY-MM-DD
+
+### Fixed
+* Fixed the ufunc docstrings, which held only the name of the C macro meant to supply them (e.g. `DOC_NUMPY__CORE_UMATH_SIN`): the docstring header is now generated by the build and included in the generated ufunc code [gh-282](https://github.com/IntelPython/mkl_umath/pull/282)
+
 ## [0.6.0] - 2026-10-15
 
 ### Added

meson.build

@@ -141,6 +141,17 @@ gen_umath_c = custom_target(
     command: [py, '@INPUT@', '-o', '@OUTPUT@']
 )
 
+gen_umath_doc_h = custom_target(
+    '_umath_doc_generated',
+    output: '_umath_doc_generated.h',
+    input: 'mkl_umath/generate_umath_doc.py',
+    command: [py, '@INPUT@', '-o', '@OUTPUT@'],
+    depend_files: [
+        'mkl_umath/ufunc_docstrings_numpy1.py',
+        'mkl_umath/ufunc_docstrings_numpy2.py'
+    ]
+)
+
 gen_loops_h = custom_target(
     'mkl_umath_loops_h',
     output: ['mkl_umath_loops.h'],
@@ -189,7 +200,10 @@ loops_dep = declare_dependency(link_with: mkl_umath_loops)
 
 py.extension_module(
     '_ufuncs',
-    sources: ['mkl_umath/src/ufuncsmodule.c', gen_umath_c, gen_loops_h],
+    sources: [
+        'mkl_umath/src/ufuncsmodule.c', gen_umath_c, gen_umath_doc_h,
+        gen_loops_h
+    ],
     include_directories: inc_np,
     dependencies: [mkl_dep, loops_dep],
     c_args: c_args + ['-DNPY_NO_DEPRECATED_API=NPY_1_7_API_VERSION'],

mkl_umath/generate_umath.py

@@ -29,8 +29,7 @@
 # 1) The `defdict` dictionary is completely different.
 # 2) In the `make_arrays` function, `cfunc_fname = f"{tname}_*"` is changed to
 # `cfunc_fname = f"mkl_umath_{tname}_*"`
-# 3) In the `make_ufuncs` function, line 988: `{doc}` is changed to `"{doc}"`
-# 4) In the `make_code` function, the string used there is different.
+# 3) In the `make_code` function, the string used there is different.
 
 """
 Generate the code to build all the internal ufuncs. At the base is the defdict:
@@ -1161,7 +1160,7 @@ def make_ufuncs(funcdict):
             f = PyUFunc_FromFuncAndDataAndSignatureAndIdentity(
                 {funcs}, {data}, {signatures}, {nloops},
                 {nin}, {nout}, {identity}, "{name}",
-                "{doc}", 0, {sig}, identity
+                {doc}, 0, {sig}, identity
             );
             if ({has_identity}) {{
                 Py_DECREF(identity);
@@ -1254,6 +1253,7 @@ def make_code(funcdict, filename):
     #include "numpy/arrayobject.h"
     #include "numpy/ufuncobject.h"
     #include "mkl_umath_loops.h"
+    #include "_umath_doc_generated.h"
     %s
 
     static int

mkl_umath/tests/test_basic.py

@@ -202,3 +202,11 @@ def test_absolute_nan_signbit(size, dtype):
             f"absolute({sign}nan) must be +nan for "
             f"{dtype.__name__} at size {size}"
         )
+
+
+@pytest.mark.parametrize("func", umaths)
+def test_docstring(func):
+    # the ufunc must carry the docstring text, not the name of its C macro
+    doc = getattr(mu, func).__doc__
+    assert "DOC_" not in doc, f"'{func}' docstring is an unexpanded macro"
+    assert "Parameters" in doc, f"'{func}' docstring is missing its body"