X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fcompiler%2Fcompiler.h;h=42245646c42ff772bcc6376ffc54ac79a1c1aca1;hb=48c1824304ac2d8aeaef7b8a55c7d9edc8992f63;hp=74e0f1835c1207454aa1fdb364d3573df31387d1;hpb=e37b906781eeddb89d2ba6c5c39e9d20e4111c18;p=ccan

diff --git a/ccan/compiler/compiler.h b/ccan/compiler/compiler.h
index 74e0f183..42245646 100644
--- a/ccan/compiler/compiler.h
+++ b/ccan/compiler/compiler.h
@@ -1,3 +1,4 @@
+/* CC0 (Public domain) - see LICENSE file for details */
 #ifndef CCAN_COMPILER_H
 #define CCAN_COMPILER_H
 #include "config.h"
@@ -61,18 +62,32 @@
 #endif
 #endif
 
-#ifndef IDEMPOTENT
+#ifndef CONST_FUNCTION
 #if HAVE_ATTRIBUTE_CONST
 /**
- * IDEMPOTENT - a function's return depends only on its argument
+ * CONST_FUNCTION - a function's return depends only on its argument
  *
  * This allows the compiler to assume that the function will return the exact
  * same value for the exact same arguments.  This implies that the function
  * must not use global variables, or dereference pointer arguments.
  */
-#define IDEMPOTENT __attribute__((const))
+#define CONST_FUNCTION __attribute__((const))
 #else
-#define IDEMPOTENT
+#define CONST_FUNCTION
+#endif
+
+#ifndef PURE_FUNCTION
+#if HAVE_ATTRIBUTE_PURE
+/**
+ * PURE_FUNCTION - a function is pure
+ *
+ * A pure function is one that has no side effects other than it's return value
+ * and uses no inputs other than it's arguments and global variables.
+ */
+#define PURE_FUNCTION __attribute__((__pure__))
+#else
+#define PURE_FUNCTION
+#endif
 #endif
 #endif