From 1ce360813decc3ddc6dfff8c1f55927e83021404 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Tue, 27 Mar 2018 14:56:29 +0200 Subject: [PATCH] util: introduce typesafe_qsort(), a typesafe version of qsort()/qsort_safe() It does two things: 1. It derives the element size from the array argument type 2. It derives the right type for the function from the array argument type Using this macro call should make the invocations of qsort() quite a bit safer. --- src/basic/util.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/basic/util.h b/src/basic/util.h index 7a98890836..0db3627e24 100644 --- a/src/basic/util.h +++ b/src/basic/util.h @@ -103,6 +103,14 @@ static inline void qsort_safe(void *base, size_t nmemb, size_t size, comparison_ qsort(base, nmemb, size, compar); } +/* A wrapper around the above, but that adds typesafety: the element size is automatically derived from the type and so + * is the prototype for the comparison function */ +#define typesafe_qsort(p, n, func) \ + ({ \ + int (*_func_)(const typeof(p[0])*, const typeof(p[0])*) = func; \ + qsort_safe((p), (n), sizeof((p)[0]), (__compar_fn_t) _func_); \ + }) + /** * Normal memcpy requires src to be nonnull. We do nothing if n is 0. */