X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/b1a20beee623c83315c3ce21abc7bcce103c6efb..d93e9a33ee30faed3945b2a7acfc46b84197d432:/utils/macros.h

diff --git a/utils/macros.h b/utils/macros.h
index bc83629..b48e6f6 100644
--- a/utils/macros.h
+++ b/utils/macros.h
@@ -61,16 +61,18 @@
 #define MLIB__STR(x) #x
 #define STR(x) MLIB__STR(x)
 
-/* --- @GLUE@ --- *
+/* --- @GLUE@, @GLUE3@ --- *
  *
  * Arguments:	@x, y@ = two sequences of tokens
+ *		@z@ = a third sequence of tokens
  *
  * Returns:	A single token formed by gluing together the macro-expansions
- *		of @x@ and @y@.
+ *		of @x@ and @y@, and @z@ for @GLUE3@.
  */
 
 #define MLIB__GLUE(x, y) x##y
 #define GLUE(x, y) MLIB__GLUE(x, y)
+#define GLUE3(x, y, z) GLUE(x, MLIB__GLUE(y, z))
 
 /* --- @STATIC_ASSERT@ --- *
  *
@@ -90,7 +92,7 @@
 	IGNORABLE extern char static_assert_failed[1 - 2*!(cond)]
 #endif
 
-/* --- @CHECK_TYPE@ ---
+/* --- @CHECK_TYPE@ --- *
  *
  * Arguments:	@expty@ = expected type of @x@
  *		@expty x@ = some object
@@ -103,7 +105,7 @@
 
 #define CHECK_TYPE(expty, x) (!sizeof(*(expty *)0 = (x)))
 
-/* --- @CONVERT_CAREFULLY@ ---
+/* --- @CONVERT_CAREFULLY@ --- *
  *
  * Arguments:	@newty@ = new type for the result
  *		@expty@ = expected type of @x@
@@ -119,6 +121,19 @@
 #define CONVERT_CAREFULLY(newty, expty, x)				\
 	(CHECK_TYPE(expty, x) + (/*unconst unvolatile*/ newty)(x))
 
+/* --- @CONTAINER@ --- *
+ *
+ * Arguments:	@type@ = the parent type, a structure or union
+ *		@mem@ = the name of the member we have a pointer to
+ *		@memty *p@ = pointer to @member@ within @type@
+ *
+ * Returns:	The address of the containing @ty@ object.
+ */
+
+#define CONTAINER(type, member, p)					\
+  (!sizeof((p) = &((type *)0)->mem) +					\
+   (type *)((unsigned char *)(p) - offsetof(type, mem)))
+
 /* --- @UNCONST@, @UNVOLATILE@, @UNQUALIFY@ --- *
  *
  * Arguments:	@type@ = a type name
@@ -144,6 +159,15 @@
 #define UNQUALIFY(type, p)						\
 	CONVERT_CAREFULLY(type *, const volatile type *, p)
 
+/* --- @EMPTY@ --- *
+ *
+ * Arguments:	---
+ *
+ * Returns:	The empty token sequence.
+ */
+
+#define EMPTY
+
 /* --- @COMMA@ --- *
  *
  * Arguments:	---
@@ -252,10 +276,10 @@
 #  define LAUNDER(x)							\
 	({ __typeof__(x) _y; __asm__("" : "=g"(_y) : "0"(x)); _y; })
 #  define ADMIRE(x)							\
-	({ __asm__("" : : "g"(x)); })
+	({ __asm__("" :: "g"(x)); })
 #  define ADMIRE_BUF(p, sz)						\
-	({ __asm__("" : : "g"(p), "g"(sz)); })
-#  define RELAX do __asm__ __volatile__("" ::: "memory"); while (0)
+	({ __asm__("" :: "m"(*(unsigned char *)p), "g"(sz) : "memory"); })
+#  define RELAX do __asm__(""); while (0)
 #endif
 
 #if CLANG_VERSION_P(3, 3)