Merge pull request #9952 from OTAkeys/at_fix_buffer_memset

at driver: allow using same buffer for command and response in at_send_cmd_get_lines()

drivers/at/at.c

@@ -121,8 +121,6 @@ ssize_t at_send_cmd_get_lines(at_dev_t *dev, const char *command,
     size_t bytes_left = len - 1;
     char *pos = resp_buf;
 
-    memset(resp_buf, '\0', len);
-
     at_drain(dev);
 
     res = at_send_cmd(dev, command, timeout);
@@ -130,6 +128,10 @@ ssize_t at_send_cmd_get_lines(at_dev_t *dev, const char *command,
         goto out;
     }
 
+    /* only clear the response buffer after sending the command,
+     * so the same buffer can be used for command and response */
+    memset(resp_buf, '\0', len);
+
     while (1) {
         res = at_readline(dev, pos, bytes_left, keep_eol, timeout);
         if (res == 0) {