diff --git a/os-posix.c b/os-posix.c
index dbf3b24..92dcc97 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -149,8 +149,8 @@ void os_set_proc_name(const char *s)
     char name[16];
     if (!s)
         return;
-    name[sizeof(name) - 1] = 0;
     strncpy(name, s, sizeof(name));
+    name[sizeof(name) - 1] = 0;
     /* Could rewrite argv[0] too, but that's a bit more complicated.
        This simple way is enough for `top'. */
     if (prctl(PR_SET_NAME, name)) {