output/csv: use intermediate time_t var, silence compiler warning

[libsigrok.git] / src / scpi / scpi.c

diff --git a/src/scpi/scpi.c b/src/scpi/scpi.c
index 0e74b32901f10e21b4a657d2ddebd57dbd401957..8d24ceea97e29c88de244fae03600a8cf52b6507 100644 (file)
--- a/src/scpi/scpi.c
+++ b/src/scpi/scpi.c
@@ -38,6 +38,7 @@ static const char *scpi_vendors[][2] = {
        { "Keysight Technologies", "Keysight" },
        { "PHILIPS", "Philips" },
        { "RIGOL TECHNOLOGIES", "Rigol" },
+       { "Siglent Technologies", "Siglent" },
 };
 
 /**
@@ -1037,7 +1038,29 @@ SR_PRIV int sr_scpi_get_block(struct sr_scpi_dev_inst *scpi,
        buf[0] = response->str[1];
        buf[1] = '\0';
        ret = sr_atol(buf, &llen);
-       if ((ret != SR_OK) || (llen == 0)) {
+       /*
+        * The form "#0..." is legal, and does not mean "empty response",
+        * but means that the number of data bytes is not known (or was
+        * not communicated) at this time. Instead the block ends at an
+        * "END MESSAGE" termination sequence. Which translates to active
+        * EOI while a text line termination is sent (CR or LF, and this
+        * text line termination is not part of the block's data value).
+        * Since this kind of #0... response is considered rare, and
+        * depends on specific support in physical transports underneath
+        * the SCPI layer, let's flag the condition and bail out with an
+        * error here, until it's found to be a genuine issue in the field.
+        *
+        * The SCPI 1999.0 specification (see page 220 and following in
+        * the "HCOPy" description) references IEEE 488.2, especially
+        * section 8.7.9 for DEFINITE LENGTH and section 8.7.10 for
+        * INDEFINITE LENGTH ARBITRARY BLOCK RESPONSE DATA. The latter
+        * with a leading "#0" length and a trailing "NL^END" marker.
+        */
+       if (ret == SR_OK && !llen) {
+               sr_err("unsupported INDEFINITE LENGTH ARBITRARY BLOCK RESPONSE");
+               ret = SR_ERR_NA;
+       }
+       if (ret != SR_OK) {
                g_mutex_unlock(&scpi->scpi_mutex);
                g_string_free(response, TRUE);
                return ret;