[glib: 1/2] gmacros: Add G_ALIGNOF superseding _g_alignof macro

[Philip Withnall <pwithnall src gnome org>]

commit 58bbdcf6c008943fe92b996a720fcf315b6e7dc9
Author: Tapasweni Pathak <tapaswenipathak gmail com>
Date:   Tue Dec 18 13:59:23 2018 +0530

    gmacros: Add G_ALIGNOF superseding _g_alignof macro

 docs/reference/glib/glib-sections.txt |  3 +++
 glib/docs.c                           | 14 +++++++++++++-
 glib/ghash.c                          |  4 ++--
 glib/glib-init.c                      | 13 ++++++-------
 glib/glib-private.h                   |  6 ------
 glib/gmacros.h                        | 11 +++++++++++
 6 files changed, 35 insertions(+), 16 deletions(-)
---
diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index 1369012ce..fb7bfd5f1 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/docs/reference/glib/glib-sections.txt
@@ -237,6 +237,9 @@ G_STRUCT_OFFSET
 <SUBSECTION>
 G_MEM_ALIGN
 
+<SUBSECTION>
+G_ALIGNOF
+
 <SUBSECTION>
 G_CONST_RETURN
 
diff --git a/glib/docs.c b/glib/docs.c
index f45a1fee8..30f6e6a56 100644
--- a/glib/docs.c
+++ b/glib/docs.c
@@ -1865,7 +1865,19 @@
  * macro will not work on an array allocated on the heap, only static
  * arrays or arrays on the stack.
  */
- 
+
+/**
+ * G_ALIGNOF
+ * @a: a type-name
+ *
+ * Return the minimum alignment required by the platform ABI for values of the given
+ * type. The address of a variable or struct member of the given type must always be
+ * a multiple of this alignment. For example, most platforms require int variables
+ * to be aligned at a 4-byte boundary, so `G_ALIGNOF (int)` is 4 on most platforms.
+ *
+ * Since: 2.60
+ */
+
 /* Miscellaneous Macros {{{1 */
 
 /**
diff --git a/glib/ghash.c b/glib/ghash.c
index af79f5b67..dac5552bd 100644
--- a/glib/ghash.c
+++ b/glib/ghash.c
@@ -31,7 +31,7 @@
 #include <string.h>  /* memset */
 
 #include "ghash.h"
-
+#include "gmacros.h"
 #include "glib-private.h"
 #include "gstrfuncs.h"
 #include "gatomic.h"
@@ -285,7 +285,7 @@ typedef struct
 } RealIter;
 
 G_STATIC_ASSERT (sizeof (GHashTableIter) == sizeof (RealIter));
-G_STATIC_ASSERT (_g_alignof (GHashTableIter) >= _g_alignof (RealIter));
+G_STATIC_ASSERT (G_ALIGNOF (GHashTableIter) >= G_ALIGNOF (RealIter));
 
 /* Each table size has an associated prime modulo (the first prime
  * lower than the table size) used to find the initial bucket. Probing
diff --git a/glib/glib-init.c b/glib/glib-init.c
index 6cb4e4a0d..6ffe7933b 100644
--- a/glib/glib-init.c
+++ b/glib/glib-init.c
@@ -20,8 +20,7 @@
 #include "config.h"
 
 #include "glib-init.h"
-
-#include "glib-private.h"
+#include "gmacros.h"
 #include "gtypes.h"
 #include "gutils.h"     /* for GDebugKey */
 #include "gconstructor.h"
@@ -40,10 +39,10 @@ G_STATIC_ASSERT (CHAR_BIT == 8);
 
 /* We assume that data pointers are the same size as function pointers... */
 G_STATIC_ASSERT (sizeof (gpointer) == sizeof (GFunc));
-G_STATIC_ASSERT (_g_alignof (gpointer) == _g_alignof (GFunc));
+G_STATIC_ASSERT (G_ALIGNOF (gpointer) == G_ALIGNOF (GFunc));
 /* ... and that all function pointers are the same size. */
 G_STATIC_ASSERT (sizeof (GFunc) == sizeof (GCompareDataFunc));
-G_STATIC_ASSERT (_g_alignof (GFunc) == _g_alignof (GCompareDataFunc));
+G_STATIC_ASSERT (G_ALIGNOF (GFunc) == G_ALIGNOF (GCompareDataFunc));
 
 /* We assume that "small" enums (those where all values fit in INT32_MIN
  * to INT32_MAX) are exactly int-sized. In particular, we assume that if
@@ -64,9 +63,9 @@ typedef enum {
 G_STATIC_ASSERT (sizeof (TestChar) == sizeof (int));
 G_STATIC_ASSERT (sizeof (TestShort) == sizeof (int));
 G_STATIC_ASSERT (sizeof (TestInt) == sizeof (int));
-G_STATIC_ASSERT (_g_alignof (TestChar) == _g_alignof (int));
-G_STATIC_ASSERT (_g_alignof (TestShort) == _g_alignof (int));
-G_STATIC_ASSERT (_g_alignof (TestInt) == _g_alignof (int));
+G_STATIC_ASSERT (G_ALIGNOF (TestChar) == G_ALIGNOF (int));
+G_STATIC_ASSERT (G_ALIGNOF (TestShort) == G_ALIGNOF (int));
+G_STATIC_ASSERT (G_ALIGNOF (TestInt) == G_ALIGNOF (int));
 
 /**
  * g_mem_gc_friendly:
diff --git a/glib/glib-private.h b/glib/glib-private.h
index 31acd9386..c002b4a6d 100644
--- a/glib/glib-private.h
+++ b/glib/glib-private.h
@@ -22,12 +22,6 @@
 #include "gwakeup.h"
 #include "gstdioprivate.h"
 
-#if defined(__GNUC__)
-# define _g_alignof(type) (__alignof__ (type))
-#else
-# define _g_alignof(type) (G_STRUCT_OFFSET (struct { char a; type b; }, b))
-#endif
-
 GMainContext *          g_get_worker_context            (void);
 gboolean                g_check_setuid                  (void);
 GMainContext *          g_main_context_new_with_next_id (guint next_id);
diff --git a/glib/gmacros.h b/glib/gmacros.h
index 437330f76..f8db7e83b 100644
--- a/glib/gmacros.h
+++ b/glib/gmacros.h
@@ -405,6 +405,17 @@
 #endif
 #endif
 
+/* Provide G_ALIGNOF alignment macro.
+ */
+
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && !defined(__cplusplus)
+#define G_ALIGNOF(type) _Alignof (type)
+#elif defined(__GNUC__)
+#define G_ALIGNOF(type) (__alignof__ (type))
+#else
+#define G_ALIGNOF(type) (G_STRUCT_OFFSET (struct { char a; type b; }, b))
+#endif
+
 /* Deprecated -- do not use. */
 #ifndef G_DISABLE_DEPRECATED
 #ifdef G_DISABLE_CONST_RETURNS