[glib] g_type_check_value, g_type_check_value_holds: accept const argument

[Philip Withnall <pwithnall src gnome org>]

commit 0c0b1bdd0a5a30caba8682dd49c81c072f9ffa29
Author: Simon McVittie <simon mcvittie collabora co uk>
Date:   Fri Aug 8 12:01:10 2014 +0100

    g_type_check_value, g_type_check_value_holds: accept const argument
    
    Conceptually, these functions clearly ought to be fine for a const
    structure. This avoids _G_TYPE_CVH (the implementation of
    G_TYPE_CHECK_VALUE_TYPE, G_VALUE_HOLDS, G_VALUE_HOLDS_BOXED etc.)
    needing to cast to a mutable GValue, which causes
    G_VALUE_HOLDS (cv, type) to issue warnings under gcc -Wcast-qual if
    cv is a const GValue *.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=734479

 gobject/gtype.c |    6 +++---
 gobject/gtype.h |    8 ++++----
 2 files changed, 7 insertions(+), 7 deletions(-)
---
diff --git a/gobject/gtype.c b/gobject/gtype.c
index b0f12f6..275a8b6 100644
--- a/gobject/gtype.c
+++ b/gobject/gtype.c
@@ -4193,14 +4193,14 @@ g_type_check_is_value_type (GType type)
 }
 
 gboolean
-g_type_check_value (GValue *value)
+g_type_check_value (const GValue *value)
 {
   return value && type_check_is_value_type_U (value->g_type);
 }
 
 gboolean
-g_type_check_value_holds (GValue *value,
-                         GType   type)
+g_type_check_value_holds (const GValue *value,
+                         GType         type)
 {
   return value && type_check_is_value_type_U (value->g_type) && g_type_is_a (value->g_type, type);
 }
diff --git a/gobject/gtype.h b/gobject/gtype.h
index 89c1bec..f771c07 100644
--- a/gobject/gtype.h
+++ b/gobject/gtype.h
@@ -2202,9 +2202,9 @@ gboolean         g_type_check_class_is_a        (GTypeClass         *g_class,
 GLIB_AVAILABLE_IN_ALL
 gboolean        g_type_check_is_value_type     (GType               type) G_GNUC_CONST;
 GLIB_AVAILABLE_IN_ALL
-gboolean        g_type_check_value             (GValue             *value) G_GNUC_PURE;
+gboolean        g_type_check_value             (const GValue       *value) G_GNUC_PURE;
 GLIB_AVAILABLE_IN_ALL
-gboolean        g_type_check_value_holds       (GValue             *value,
+gboolean        g_type_check_value_holds       (const GValue       *value,
                                                 GType               type) G_GNUC_PURE;
 GLIB_AVAILABLE_IN_ALL
 gboolean         g_type_test_flags              (GType               type,
@@ -2255,7 +2255,7 @@ const gchar *    g_type_name_from_class         (GTypeClass       *g_class);
   __r; \
 }))
 #  define _G_TYPE_CVH(vl, gt)             (G_GNUC_EXTENSION ({ \
-  GValue *__val = (GValue*) vl; GType __t = gt; gboolean __r; \
+  const GValue *__val = (const GValue*) vl; GType __t = gt; gboolean __r; \
   if (!__val) \
     __r = FALSE; \
   else if (__val->g_type == __t)               \
@@ -2267,7 +2267,7 @@ const gchar *    g_type_name_from_class         (GTypeClass       *g_class);
 #else  /* !__GNUC__ */
 #  define _G_TYPE_CIT(ip, gt)             (g_type_check_instance_is_a ((GTypeInstance*) ip, gt))
 #  define _G_TYPE_CCT(cp, gt)             (g_type_check_class_is_a ((GTypeClass*) cp, gt))
-#  define _G_TYPE_CVH(vl, gt)             (g_type_check_value_holds ((GValue*) vl, gt))
+#  define _G_TYPE_CVH(vl, gt)             (g_type_check_value_holds ((const GValue*) vl, gt))
 #endif /* !__GNUC__ */
 /**
  * G_TYPE_FLAG_RESERVED_ID_BIT: