New PURE_FUNCTION, CONST_FUNCTION macros.

diff --git a/src/libpspp/ChangeLog b/src/libpspp/ChangeLog
index 1cb917d179e47fa6b46500113304a7afb6dedd71..58e74d6f3dc023215df58341f229281d0eac9d4b 100644 (file)
--- a/src/libpspp/ChangeLog
+++ b/src/libpspp/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 31 15:49:46 2006  Ben Pfaff  <blp@gnu.org>
+
+       * compiler.h: (macro CONST_FUNCTION) New macro.
+       (macro PURE_FUNCTION) New macro.
+
 Sun Jul 16 21:07:35 2006  Ben Pfaff  <blp@gnu.org>
 
        * message.c: (static int messages_disabled) New variable.

diff --git a/src/libpspp/compiler.h b/src/libpspp/compiler.h
index 8c2c3abd2ea6a808761eed046dce287f277ffaf9..b7df277540574ba6021c8d1363309a88c7071958 100644 (file)
--- a/src/libpspp/compiler.h
+++ b/src/libpspp/compiler.h
@@ -32,12 +32,21 @@
 #define ATTRIBUTE(X)
 #endif
 
+/* Marks a function argument as possibly not used. */
 #define UNUSED ATTRIBUTE ((unused))
+
+/* Marks a function that will never return. */
 #define NO_RETURN ATTRIBUTE ((noreturn))
+
+/* Mark a function as taking a printf- or scanf-like format
+   string as its FMT'th argument and that the FIRST'th argument
+   is the first one to be checked against the format string. */
 #define PRINTF_FORMAT(FMT, FIRST) ATTRIBUTE ((format (printf, FMT, FIRST)))
 #define SCANF_FORMAT(FMT, FIRST) ATTRIBUTE ((format (scanf, FMT, FIRST)))
 
-/* This attribute was added late in the GCC 2.x cycle. */
+/* Tells the compiler that a function may be treated as if any
+   non-`NULL' pointer it returns cannot alias any other pointer
+   valid when the function returns. */
 #if __GNUC__ > 2
 #define MALLOC_LIKE ATTRIBUTE ((malloc))
 #else
@@ -51,4 +60,24 @@
 #define WARN_UNUSED_RESULT
 #endif
 
+/* This attribute indicates that the function does not examine
+   any values except its arguments, and have no effects except
+   the return value.  A function that has pointer arguments and
+   examines the data pointed to must _not_ be declared
+   `const'.  */
+#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 5)
+#define CONST_FUNCTION ATTRIBUTE ((const))
+#else
+#define CONST_FUNCTION
+#endif
+
+/* This attribute indicates that the function has no effects
+   except the return value and its return value depends only on
+   the parameters and/or global variables. */
+#if __GNUC__ > 2
+#define PURE_FUNCTION ATTRIBUTE ((pure))
+#else
+#define PURE_FUNCTION
+#endif
+
 #endif /* compiler.h */