dmm/metex14: unbreak packet request helper return code

[libsigrok.git] / src / dmm / metex14.c

diff --git a/src/dmm/metex14.c b/src/dmm/metex14.c
index d363c550921e4fe55773aef2b4779f8b7b8a608f..d93052a85b84bc7cbfbe50b5b3c266df50dbf665 100644 (file)
--- a/src/dmm/metex14.c
+++ b/src/dmm/metex14.c
@@ -22,7 +22,6 @@
  *
  * Metex 14-bytes ASCII protocol parser.
  *
- * @internal
  * This should work for various multimeters which use this kind of protocol,
  * even though there is some variation in which modes each DMM supports.
  *
@@ -333,10 +332,19 @@ static gboolean flags_valid(const struct metex14_info *info)
 SR_PRIV int sr_metex14_packet_request(struct sr_serial_dev_inst *serial)
 {
        const uint8_t wbuf = 'D';
+       size_t wrlen;
+       int ret;
 
        sr_spew("Requesting DMM packet.");
 
-       return serial_write_blocking(serial, &wbuf, 1, 0);
+       wrlen = sizeof(wbuf);
+       ret = serial_write_blocking(serial, &wbuf, wrlen, 0);
+       if (ret < 0)
+               return ret;
+       if ((size_t)ret != wrlen)
+               return SR_ERR_IO;
+
+       return SR_OK;
 }
 #endif