X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/catacomb/blobdiff_plain/11b179777b6b29afe0c960f62d7e2ea33b01cccd..fac645f7780c7673775f09fe625651f600f7ee7b:/base/dispatch.h

diff --git a/base/dispatch.h b/base/dispatch.h
index 612cfcd3..bbb81f30 100644
--- a/base/dispatch.h
+++ b/base/dispatch.h
@@ -138,8 +138,34 @@ stcls ret ext argdecls { rtn dflt args; }
 
 #endif
 
+/* --- Some macros for producing useful debugging --- */
+
+#define DISPATCH_PICK_COND(what, func, cond) do {			\
+  if (cond) {								\
+    dispatch_debug("picked `%s' for `%s'", #func, #what);		\
+    return (func);							\
+  }									\
+} while (0)
+#define DISPATCH_PICK_FALLBACK(what, func) do {				\
+  dispatch_debug("using default `%s'", #what);				\
+  return (func);							\
+} while (0)
+
 /*----- Functions provided ------------------------------------------------*/
 
+/* --- @dispatch_debug@ --- *
+ *
+ * Arguments:	@const char *fmt@ = a format string
+ *		@...@ = additional arguments
+ *
+ * Returns:	---
+ *
+ * Use:		Writes a formatted message to standard output if dispatch
+ *		debugging is enabled.
+ */
+
+extern void dispatch_debug(const char */*fmt*/, ...);
+
 /* --- @cpu_feature_p@ --- *
  *
  * Arguments:	@unsigned feat@ = a @CPUFEAT_...@ code