diff --git a/lib/memdebug.h b/lib/memdebug.h
index 7b7b713e2..48f487d67 100644
--- a/lib/memdebug.h
+++ b/lib/memdebug.h
@@ -82,6 +82,9 @@ int curl_fclose(FILE *file, int line, const char *source);
 /* sclose is probably already defined, redefine it! */
 #undef sclose
 #define sclose(sockfd) curl_sclose(sockfd,__LINE__,__FILE__)
+/* ares-adjusted define: */
+#undef closesocket
+#define closesocket(sockfd) curl_sclose(sockfd,__LINE__,__FILE__)
 
 #undef fopen
 #define fopen(file,mode) curl_fopen(file,mode,__LINE__,__FILE__)