1 files changed, 23 insertions, 0 deletions
diff --git a/opt.h b/opt.h
new file mode 100644
index 0000000..0492226
--- /dev/null
+++ b/opt.h
@@ -0,0 +1,23 @@
+// Mike wrote this.
+
+#define FOR_OPTS(argc, argv) \
+    for ( \
+        const char *_p = (--(argc), *++(argv)), *_p1; \
+        argc && *_p == '-' && *++_p && \
+            (*_p != '-' || _p[1] || (++(argv), --(argc), 0)); \
+        _p = *++(argv), --(argc), (void)(_p1) /* suppress unused warning */ \
+    ) \
+        while (*_p) \
+            switch (*_p++) \
+                if (0) default: { \
+                    fprintf(stderr, "invalid option: -%c\n", _p[-1]); \
+                    usage(); \
+                } \
+                else /* { cases/code here } */
+
+#define OPTARG(argc, argv) \
+    (*_p ? (_p1 = _p, _p = "", _p1) : (*(--(argc), ++(argv)) ? *(argv) : \
+        (fprintf(stderr, "missing argument for option -%c\n", _p[-1]), \
+            usage(), (char *)0)))
+
+// vi: sw=4 ts=4 noet tw=80 cc=80