diff --git a/libkeke_array.c b/libkeke_array.c
index 6a4227d..935633b 100644
--- a/libkeke_array.c
+++ b/libkeke_array.c
@@ -185,7 +185,16 @@ void *keke_array_find_start(KekeArray *array, void *start, size_t size) {
     return NULL;
 }
 
-int compar(const void *a, const void *b, void *size_v) {
+/* Windows uses qsort_s rather than qsort_r and wants a BSD-style comparison function.
+ * This will transparently switch the comparison function based on platform. */
+#if _WIN32
+#define qsort_r qsort_s
+#define compar(a, b, size_v) _compar(size_v, a, b)
+int _compar(void *size_v, const void *a, const void *b) {
+#else
+#define compar(a, b, size_v) _compar(a, b, size_v)
+int _compar(const void *a, const void *b, void *size_v) {
+#endif
 	size_t size = *(size_t *) size_v;
 #if defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
 	return memcmp(a, b, size);
@@ -219,11 +228,11 @@ int compar(const void *a, const void *b, void *size_v) {
 }
 
 void keke_array_qsort(KekeArray *array) {
-	qsort_r(array->content, array->len, array->type_size, compar, &array->type_size);
+	qsort_r(array->content, array->len, array->type_size, _compar, &array->type_size);
 }
 
 void keke_array_qsort_header(KekeArray *array, size_t start_header_size) {
-	qsort_r(array->content, array->len, array->type_size, compar, &start_header_size);
+	qsort_r(array->content, array->len, array->type_size, _compar, &start_header_size);
 }
 
 typedef int (*Rng_fun)(int);