diff --git a/util.c b/util.c
index 20311fc..0658bc0 100644
--- a/util.c
+++ b/util.c
@@ -224,8 +224,7 @@
 		msg = "CONT";
 	if (op == PTRACE_DETACH)
 		msg = "DETACH";
-	fprintf(stderr, "strace: ptrace(PTRACE_%s,1,%d): %s\n",
-			msg, sig, strerror(err));
+	perror_msg("ptrace(PTRACE_%s,1,%d)", msg, sig);
 	return -1;
 }