ref: d399a6b23051335ce3107f11822ae352816fcd50
parent: bb1432c0ad0ba2955df9483dde67a987fb946ed8
author: Simon Tatham <anakin@pobox.com>
date: Sat Dec 11 06:32:25 EST 2021
tree234: avoid an uninitialised-variable warning.
Apparently, some compilers can't work out that the pattern
if (!t->root) { special-case handler followed by early return }
n = t->root;
while (n) { ... }
will execute the while loop at least once, on the grounds that the
_first_ test for n being non-NULL must pass, because we initialised n
from t->root which can't be NULL on any code path where we didn't take
the early return. So they might give an uninitialised-variable warning
for the variable 'ki', which is initialised inside the while loop.
Compilers, eh. But it's easy enough to turn the while into a do-while,
so that even the least alert compiler will know it runs at least once.
--- a/tree234.c
+++ b/tree234.c
@@ -332,7 +332,7 @@
}
n = t->root;
- while (n) {+ do { LOG((" node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",n,
n->kids[0], n->counts[0], n->elems[0],
@@ -385,7 +385,7 @@
if (!n->kids[ki])
break;
n = n->kids[ki];
- }
+ } while (n);
add234_insert(NULL, e, NULL, &t->root, n, ki);