pythongh-118124: Use static_assert() in Py_BUILD_ASSERT()

vstinner · Apr 29, 2024 · efbd483 · efbd483
1 parent 23d0371
commit efbd483
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/Include/pymacro.h b/Include/pymacro.h
@@ -61,9 +61,15 @@
 #define Py_BUILD_ASSERT_EXPR(cond) \
     (sizeof(char [1 - 2*!(cond)]) - 1)
 
-#define Py_BUILD_ASSERT(cond)  do {         \
-        (void)Py_BUILD_ASSERT_EXPR(cond);   \
-    } while(0)
+#if __STDC_VERSION__ >= 201112L
+   // Use static_assert() on C11 and newer
+#  define Py_BUILD_ASSERT(cond) static_assert((cond), "")
+#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
 

diff --git a/Misc/NEWS.d/next/C API/2024-04-29-17-44-15.gh-issue-118124.czQQ9G.rst b/Misc/NEWS.d/next/C API/2024-04-29-17-44-15.gh-issue-118124.czQQ9G.rst
@@ -0,0 +1,3 @@
+Use ``static_assert()`` in :c:macro:`Py_BUILD_ASSERT` on C11 and newer to
+fix :c:macro:`Py_BUILD_ASSERT` on non-constant expressions. Patch by Victor
+Stinner.