rcx

commit bd81806d6b29848da7478def0afd7758608a5a9b
parent 58ec1e65dd8320654ce9ba920f6847270cddc384
Author: Robert Russell <robertrussell.72001@gmail.com>
Date:   Thu, 23 Feb 2023 22:50:57 -0800

Add VA_DEFAULT macro

Diffstat:
M
inc/def.h
 | 
9
++++++++-

1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/inc/def.h b/inc/def.h
@@ -7,6 +7,12 @@
 #define JOIN_AUX(a,b) a##b
 #define JOIN(a,b) JOIN_AUX(a,b)
 
+/* VA_DEFAULT is a helper for writing macros with an optional argument. Usage:
+ *     #define MY_MACRO(...) VA_DEFAULT(,##__VA_ARGS__, "default")
+ *     MY_MACRO()         ->   "default"
+ *     MY_MACRO("whoa")   ->   "whoa" */
+#define VA_DEFAULT(_, v, ...) v
+
 #define LEN(a) (sizeof (a) / sizeof (a)[0])
 #define MIN(a,b) ((a) < (b) ? (a) : (b))
 #define MAX(a,b) ((a) > (b) ? (a) : (b))
@@ -32,7 +38,8 @@
 /* Here, roughly speaking, "word" means the largest unit that the machine can
  * operate on in one instruction (typically the same width as registers and
  * the bus). This detection is probably wrong on some weird machines, but this
- * is the best we can do in C. */
+ * is the best we can do in C.
+ * XXX: Is this used anywhere? We should probably just assume 64 bit. */
 #if   UINTPTR_MAX == UINT32_MAX
 #define WORD_SIZE 4
 #elif UINTPTR_MAX == UINT64_MAX