[glib: 1/2] gmacros: Use _Static_assert only for non-expr static assert



commit b169b5a45d1e7a31359dfb25f75886cad65274fb
Author: Nirbheek Chauhan <nirbheek chauhan gmail com>
Date:   Mon Jul 1 13:41:58 2019 +0000

    gmacros: Use _Static_assert only for non-expr static assert
    
    We can't actually use it inside an expression, so keep the old macro
    for that. Also add a test so that this doesn't break the next time we
    change it.
    
    See: https://gitlab.gnome.org/GNOME/glib/merge_requests/955#note_542646

 glib/gmacros.h      |  8 +++++++-
 glib/tests/macros.c | 10 ++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)
---
diff --git a/glib/gmacros.h b/glib/gmacros.h
index 1c8d64699..fd81416dd 100644
--- a/glib/gmacros.h
+++ b/glib/gmacros.h
@@ -734,13 +734,19 @@
 #ifndef __GI_SCANNER__ /* The static assert macro really confuses the introspection parser */
 #define G_PASTE_ARGS(identifier1,identifier2) identifier1 ## identifier2
 #define G_PASTE(identifier1,identifier2)      G_PASTE_ARGS (identifier1, identifier2)
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+#define G_STATIC_ASSERT(expr) _Static_assert (expr, "Expression evaluates to false")
+#elif defined(__cplusplus) && __cplusplus >= 201103L
+#define G_STATIC_ASSERT(expr) static_assert (expr, "Expression evaluates to false")
+#else
 #ifdef __COUNTER__
 #define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __COUNTER__)[(expr) 
? 1 : -1] G_GNUC_UNUSED
 #else
 #define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __LINE__)[(expr) ? 
1 : -1] G_GNUC_UNUSED
 #endif
+#endif /* __STDC_VERSION__ */
 #define G_STATIC_ASSERT_EXPR(expr) ((void) sizeof (char[(expr) ? 1 : -1]))
-#endif
+#endif /* !__GI_SCANNER__ */
 
 /* Provide a string identifying the current code position */
 #if defined(__GNUC__) && (__GNUC__ < 3) && !defined(__cplusplus)
diff --git a/glib/tests/macros.c b/glib/tests/macros.c
index 7fc1d6086..89a1322ee 100644
--- a/glib/tests/macros.c
+++ b/glib/tests/macros.c
@@ -20,6 +20,15 @@
 
 #include <glib.h>
 
+/* Test that G_STATIC_ASSERT_EXPR can be used as an expression */
+static void
+test_assert_static (void)
+{
+  G_STATIC_ASSERT (4 == 4);
+  if (G_STATIC_ASSERT_EXPR (1 == 1), sizeof (gchar) == 2)
+    g_assert_not_reached ();
+}
+
 /* Test G_ALIGNOF() gives the same results as the G_STRUCT_OFFSET fallback. This
  * should be the minimal alignment for the given type.
  *
@@ -48,6 +57,7 @@ main (int   argc,
   g_test_init (&argc, &argv, NULL);
 
   g_test_add_func ("/alignof/fallback", test_alignof_fallback);
+  g_test_add_func ("/assert/static", test_assert_static);
 
   return g_test_run ();
 }


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