X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcompiler%2Fcompiler.h;h=74e0f1835c1207454aa1fdb364d3573df31387d1;hp=242ef84d133ddb65ea378bdfcc6585a7f46d7bd8;hb=e37b906781eeddb89d2ba6c5c39e9d20e4111c18;hpb=18636637ee013ef828cb04b2b7bb4a4922324475

diff --git a/ccan/compiler/compiler.h b/ccan/compiler/compiler.h
index 242ef84d..74e0f183 100644
--- a/ccan/compiler/compiler.h
+++ b/ccan/compiler/compiler.h
@@ -2,99 +2,154 @@
 #define CCAN_COMPILER_H
 #include "config.h"
 
+#ifndef COLD
 #if HAVE_ATTRIBUTE_COLD
 /**
- * COLD_ATTRIBUTE - a function is unlikely to be called.
+ * COLD - a function is unlikely to be called.
  *
  * Used to mark an unlikely code path and optimize appropriately.
  * It is usually used on logging or error routines.
  *
  * Example:
- * static void COLD_ATTRIBUTE moan(const char *reason)
+ * static void COLD moan(const char *reason)
  * {
  *	fprintf(stderr, "Error: %s (%s)\n", reason, strerror(errno));
  * }
  */
-#define COLD_ATTRIBUTE __attribute__((cold))
+#define COLD __attribute__((cold))
 #else
-#define COLD_ATTRIBUTE
+#define COLD
+#endif
 #endif
 
+#ifndef NORETURN
+#if HAVE_ATTRIBUTE_NORETURN
+/**
+ * NORETURN - a function does not return
+ *
+ * Used to mark a function which exits; useful for suppressing warnings.
+ *
+ * Example:
+ * static void NORETURN fail(const char *reason)
+ * {
+ *	fprintf(stderr, "Error: %s (%s)\n", reason, strerror(errno));
+ *	exit(1);
+ * }
+ */
+#define NORETURN __attribute__((noreturn))
+#else
+#define NORETURN
+#endif
+#endif
+
+#ifndef PRINTF_FMT
 #if HAVE_ATTRIBUTE_PRINTF
 /**
- * PRINTF_ATTRIBUTE - a function takes printf-style arguments
+ * PRINTF_FMT - a function takes printf-style arguments
  * @nfmt: the 1-based number of the function's format argument.
  * @narg: the 1-based number of the function's first variable argument.
  *
  * This allows the compiler to check your parameters as it does for printf().
  *
  * Example:
- * void PRINTF_ATTRIBUTE(2,3) my_printf(const char *prefix,
- *					const char *fmt, ...);
+ * void PRINTF_FMT(2,3) my_printf(const char *prefix, const char *fmt, ...);
  */
-#define PRINTF_ATTRIBUTE(nfmt, narg) \
+#define PRINTF_FMT(nfmt, narg) \
 	__attribute__((format(__printf__, nfmt, narg)))
 #else
-#define PRINTF_ATTRIBUTE(nfmt, narg)
+#define PRINTF_FMT(nfmt, narg)
+#endif
 #endif
 
+#ifndef IDEMPOTENT
 #if HAVE_ATTRIBUTE_CONST
 /**
- * IDEMPOTENT_ATTRIBUTE - a function's return depends only on its argument
+ * IDEMPOTENT - 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 __attribute__((const))
+#define IDEMPOTENT __attribute__((const))
 #else
-#define IDEMPOTENT_ATTRIBUTE
+#define IDEMPOTENT
+#endif
 #endif
 
 #if HAVE_ATTRIBUTE_UNUSED
+#ifndef UNNEEDED
 /**
- * UNNEEDED_ATTRIBUTE - a parameter/variable/function may not be needed
+ * UNNEEDED - a variable/function may not be needed
  *
- * This suppresses warnings about unused variables or parameters, but tells
+ * This suppresses warnings about unused variables or functions, but tells
  * the compiler that if it is unused it need not emit it into the source code.
  *
  * Example:
  * // With some preprocessor options, this is unnecessary.
- * static UNNEEDED_ATTRIBUTE int counter;
+ * static UNNEEDED int counter;
  *
  * // With some preprocessor options, this is unnecessary.
- * static UNNEEDED_ATTRIBUTE void add_to_counter(int add)
+ * static UNNEEDED void add_to_counter(int add)
  * {
  *	counter += add;
  * }
  */
-#define UNNEEDED_ATTRIBUTE __attribute__((unused))
+#define UNNEEDED __attribute__((unused))
+#endif
 
+#ifndef NEEDED
 #if HAVE_ATTRIBUTE_USED
 /**
- * NEEDED_ATTRIBUTE - a parameter/variable/function is needed
+ * NEEDED - a variable/function is needed
  *
- * This suppresses warnings about unused variables or parameters, but tells
+ * This suppresses warnings about unused variables or functions, but tells
  * the compiler that it must exist even if it (seems) unused.
  *
  * Example:
  *	// Even if this is unused, these are vital for debugging.
- *	static UNNEEDED_ATTRIBUTE int counter;
- *	static UNNEEDED_ATTRIBUTE void dump_counter(void)
+ *	static NEEDED int counter;
+ *	static NEEDED void dump_counter(void)
  *	{
  *		printf("Counter is %i\n", counter);
  *	}
  */
-#define NEEDED_ATTRIBUTE __attribute__((used))
+#define NEEDED __attribute__((used))
 #else
 /* Before used, unused functions and vars were always emitted. */
-#define NEEDED_ATTRIBUTE __attribute__((unused))
+#define NEEDED __attribute__((unused))
+#endif
+#endif
+
+#ifndef UNUSED
+/**
+ * UNUSED - a parameter is unused
+ *
+ * Some compilers (eg. gcc with -W or -Wunused) warn about unused
+ * function parameters.  This suppresses such warnings and indicates
+ * to the reader that it's deliberate.
+ *
+ * Example:
+ *	// This is used as a callback, so needs to have this prototype.
+ *	static int some_callback(void *unused UNUSED)
+ *	{
+ *		return 0;
+ *	}
+ */
+#define UNUSED __attribute__((unused))
 #endif
 #else
-#define UNNEEDED_ATTRIBUTE
-#define NEEDED_ATTRIBUTE
+#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?
@@ -114,7 +169,7 @@
  *	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";
@@ -136,4 +191,26 @@
 /* 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.
+ *
+ * Used to mark a function where it is extremely unlikely that the caller
+ * can ignore the result, eg realloc().
+ *
+ * Example:
+ * // buf param may be freed by this; need return value!
+ * static char *WARN_UNUSED_RESULT enlarge(char *buf, unsigned *size)
+ * {
+ *	return realloc(buf, (*size) *= 2);
+ * }
+ */
+#define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
+#else
+#define WARN_UNUSED_RESULT
+#endif
+#endif
 #endif /* CCAN_COMPILER_H */