python
diff --git a/‎Include/pymacro.h‎
Lines changed: 33 additions & 16 deletions b/‎Include/pymacro.h‎
Lines changed: 33 additions & 16 deletions
diff --git a/‎Lib/test/test_cext/extension.c‎
Lines changed: 5 additions & 0 deletions b/‎Lib/test/test_cext/extension.c‎
Lines changed: 5 additions & 0 deletions
diff --git a/‎Lib/test/test_cppext/extension.cpp‎
Lines changed: 4 additions & 0 deletions b/‎Lib/test/test_cppext/extension.cpp‎
Lines changed: 4 additions & 0 deletions
diff --git a/‎Misc/NEWS.d/next/C API/2024-04-29-17-44-15.gh-issue-118124.czQQ9G.rst‎
Lines changed: 3 additions & 0 deletions b/‎Misc/NEWS.d/next/C API/2024-04-29-17-44-15.gh-issue-118124.czQQ9G.rst‎
Lines changed: 3 additions & 0 deletions
@@ -46,24 +46,41 @@
 /* Argument must be a char or an int in [-128, 127] or [0, 255]. */
 #define Py_CHARMASK(c) ((unsigned char)((c) & 0xff))
 
-/* Assert a build-time dependency, as an expression.
-
-   Your compile will fail if the condition isn't true, or can't be evaluated
-   by the compiler. This can be used in an expression: its value is 0.
-
-   Example:
-
-   #define foo_to_char(foo)  \
-       ((char *)(foo)        \
-        + Py_BUILD_ASSERT_EXPR(offsetof(struct foo, string) == 0))
-
-   Written by Rusty Russell, public domain, http://ccodearchive.net/ */
-#define Py_BUILD_ASSERT_EXPR(cond) \
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+#  define Py_BUILD_ASSERT_EXPR(cond) \
+    ((void)sizeof(struct { int dummy; _Static_assert(cond, #cond); }), \
+     0)
+#else
+   /* Assert a build-time dependency, as an expression.
+    *
+    * Your compile will fail if the condition isn't true, or can't be evaluated
+    * by the compiler. This can be used in an expression: its value is 0.
+    *
+    * Example:
+    *
+    * #define foo_to_char(foo)  \
+    *     ((char *)(foo)        \
+    *      + Py_BUILD_ASSERT_EXPR(offsetof(struct foo, string) == 0))
+    *
+    * Written by Rusty Russell, public domain, http://ccodearchive.net/
+    */
+#  define Py_BUILD_ASSERT_EXPR(cond) \
     (sizeof(char [1 - 2*!(cond)]) - 1)
+#endif
 
-#define Py_BUILD_ASSERT(cond)  do {         \
-        (void)Py_BUILD_ASSERT_EXPR(cond);   \
-    } while(0)
+#if ((defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) \
+     || (defined(__cplusplus) && __cplusplus >= 201103L))
+   // Use static_assert() on C11 and newer
+#  define Py_BUILD_ASSERT(cond) \
+        do { \
+            static_assert((cond), #cond); \
+        } while (0)
+#else
+#  define Py_BUILD_ASSERT(cond)  \
+        do { \
+            (void)Py_BUILD_ASSERT_EXPR(cond); \
+        } while(0)
+#endif
 
 /* Get the number of elements in a visible array
 
 
@@ -44,6 +44,11 @@ _testcext_exec(PyObject *module)
         return -1;
     }
 #endif
+
+    // test Py_BUILD_ASSERT() and Py_BUILD_ASSERT_EXPR()
+    Py_BUILD_ASSERT(sizeof(int) == sizeof(unsigned int));
+    assert(Py_BUILD_ASSERT_EXPR(sizeof(int) == sizeof(unsigned int)) == 0);
+
     return 0;
 }
 
 
@@ -225,6 +225,10 @@ _testcppext_exec(PyObject *module)
     if (!result) return -1;
     Py_DECREF(result);
 
+    // test Py_BUILD_ASSERT() and Py_BUILD_ASSERT_EXPR()
+    Py_BUILD_ASSERT(sizeof(int) == sizeof(unsigned int));
+    assert(Py_BUILD_ASSERT_EXPR(sizeof(int) == sizeof(unsigned int)) == 0);
+
     return 0;
 }
 
 
@@ -0,0 +1,3 @@
+Fix :c:macro:`Py_BUILD_ASSERT` and :c:macro:`Py_BUILD_ASSERT_EXPR` for
+non-constant expressions: use ``static_assert()`` on C11 and newer.
+Patch by Victor Stinner.
Original file line number	Diff line number	Diff line change
`@@ -44,6 +44,11 @@ _testcext_exec(PyObject *module)`
`44`	`44`	`return -1;`
`45`	`45`	`}`
`46`	`46`	`#endif`
	`47`	`+`
	`48`	`+ // test Py_BUILD_ASSERT() and Py_BUILD_ASSERT_EXPR()`
	`49`	`+ Py_BUILD_ASSERT(sizeof(int) == sizeof(unsigned int));`
	`50`	`+ assert(Py_BUILD_ASSERT_EXPR(sizeof(int) == sizeof(unsigned int)) == 0);`
	`51`	`+`
`47`	`52`	`return 0;`
`48`	`53`	`}`
`49`	`54`
Original file line number	Diff line number	Diff line change
`@@ -225,6 +225,10 @@ _testcppext_exec(PyObject *module)`
`225`	`225`	`if (!result) return -1;`
`226`	`226`	`Py_DECREF(result);`
`227`	`227`
	`228`	`+ // test Py_BUILD_ASSERT() and Py_BUILD_ASSERT_EXPR()`
	`229`	`+ Py_BUILD_ASSERT(sizeof(int) == sizeof(unsigned int));`
	`230`	`+ assert(Py_BUILD_ASSERT_EXPR(sizeof(int) == sizeof(unsigned int)) == 0);`
	`231`	`+`
`228`	`232`	`return 0;`
`229`	`233`	`}`
`230`	`234`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+Fix :c:macro:`Py_BUILD_ASSERT` and :c:macro:`Py_BUILD_ASSERT_EXPR` for
	`2`	+non-constant expressions: use ``static_assert()`` on C11 and newer.
	`3`	`+Patch by Victor Stinner.`