X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcompiler%2Fcompiler.h;h=42245646c42ff772bcc6376ffc54ac79a1c1aca1;hp=1e0d8efbaacc1be66aa291f861560a513b69887a;hb=48c1824304ac2d8aeaef7b8a55c7d9edc8992f63;hpb=6e1cdb3d8b6fac56b24403e2d0b86810a9ccffb2

diff --git a/ccan/compiler/compiler.h b/ccan/compiler/compiler.h
index 1e0d8efb..42245646 100644
--- a/ccan/compiler/compiler.h
+++ b/ccan/compiler/compiler.h
@@ -1,7 +1,9 @@
+/* CC0 (Public domain) - see LICENSE file for details */
 #ifndef CCAN_COMPILER_H
 #define CCAN_COMPILER_H
 #include "config.h"
 
+#ifndef COLD
 #if HAVE_ATTRIBUTE_COLD
 /**
  * COLD - a function is unlikely to be called.
@@ -19,7 +21,9 @@
 #else
 #define COLD
 #endif
+#endif
 
+#ifndef NORETURN
 #if HAVE_ATTRIBUTE_NORETURN
 /**
  * NORETURN - a function does not return
@@ -37,7 +41,9 @@
 #else
 #define NORETURN
 #endif
+#endif
 
+#ifndef PRINTF_FMT
 #if HAVE_ATTRIBUTE_PRINTF
 /**
  * PRINTF_FMT - a function takes printf-style arguments
@@ -54,21 +60,39 @@
 #else
 #define PRINTF_FMT(nfmt, narg)
 #endif
+#endif
 
+#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
 
 #if HAVE_ATTRIBUTE_UNUSED
+#ifndef UNNEEDED
 /**
  * UNNEEDED - a variable/function may not be needed
  *
@@ -86,7 +110,9 @@
  * }
  */
 #define UNNEEDED __attribute__((unused))
+#endif
 
+#ifndef NEEDED
 #if HAVE_ATTRIBUTE_USED
 /**
  * NEEDED - a variable/function is needed
@@ -107,7 +133,9 @@
 /* Before used, unused functions and vars were always emitted. */
 #define NEEDED __attribute__((unused))
 #endif
+#endif
 
+#ifndef UNUSED
 /**
  * UNUSED - a parameter is unused
  *
@@ -123,12 +151,20 @@
  *	}
  */
 #define UNUSED __attribute__((unused))
+#endif
 #else
+#ifndef UNNEEDED
 #define UNNEEDED
+#endif
+#ifndef NEEDED
 #define NEEDED
+#endif
+#ifndef UNUSED
 #define UNUSED
 #endif
+#endif
 
+#ifndef IS_COMPILE_CONSTANT
 #if HAVE_BUILTIN_CONSTANT_P
 /**
  * IS_COMPILE_CONSTANT - does the compiler know the value of this expression?
@@ -148,7 +184,7 @@
  *	const char *greek_name(enum greek greek);
  *
  *	// Inline version.
- *	static inline char *_greek_name(enum greek greek)
+ *	static inline const char *_greek_name(enum greek greek)
  *	{
  *		switch (greek) {
  *		case ALPHA: return "alpha";
@@ -170,7 +206,9 @@
 /* If we don't know, assume it's not. */
 #define IS_COMPILE_CONSTANT(expr) 0
 #endif
+#endif
 
+#ifndef WARN_UNUSED_RESULT
 #if HAVE_WARN_UNUSED_RESULT
 /**
  * WARN_UNUSED_RESULT - warn if a function return value is unused.
@@ -189,4 +227,5 @@
 #else
 #define WARN_UNUSED_RESULT
 #endif
+#endif
 #endif /* CCAN_COMPILER_H */