gr-iio: pluto source /sink fails to set paramter if german locale is used

pluto source / sink fails to set hardwaregain with

gr::log :WARN: iio::device::set_params - Unable to write attribute in_voltage0_hardwaregain: -22
gr::log :WARN: iio::device::set_params - Unable to write attribute out_voltage0_hardwaregain: -22

gain values are treated as double. The conversion std::to_string() uses the locale setting.
So in the US std::to_string(10.) leads to "10.0" while in Germany the result is "10,0" which the pluto handles as error.
This problem only exists if real values are converted. So check if the converted string contains a , as separator and change it to a dot .

Signed-off-by: Volker Schroer <3470424+dl1ksv@users.noreply.github.com>

3 files changed, 12 insertions, 7 deletions

diff --git a/gr-iio/lib/device_source_impl.cc b/gr-iio/lib/device_source_impl.cc
index 59f5eb306..d837a06eb 100644
--- a/gr-iio/lib/device_source_impl.cc
+++ b/gr-iio/lib/device_source_impl.cc
@@ -92,7 +92,8 @@ void device_source_impl::set_params(struct iio_device* phy,
             ret = iio_device_debug_attr_write(phy, attr, val.c_str());
         if (ret < 0) {
             GR_LOG_WARN(logger,
-                        boost::format("Unable to write attribute %s: %d") % key % ret);
+                        boost::format("Unable to write attribute %s: %d %s") % key % ret %
+                            val);
         }
     }
 }
diff --git a/gr-iio/lib/fmcomms2_sink_impl.cc b/gr-iio/lib/fmcomms2_sink_impl.cc
index dea67e912..ceaaf2505 100644
--- a/gr-iio/lib/fmcomms2_sink_impl.cc
+++ b/gr-iio/lib/fmcomms2_sink_impl.cc
@@ -185,9 +185,11 @@ void fmcomms2_sink_impl::set_attenuation(size_t chan, double attenuation)
         throw std::runtime_error("Channel out of range for this device");
     }
     std::vector<std::string> params;
-
-    params.push_back("out_voltage" + std::to_string(chan) +
-                     "_hardwaregain=" + std::to_string(-attenuation));
+    std::string att_value = std::to_string(-attenuation);
+    std::string::size_type idx = att_value.find(',');
+    if (idx != std::string::npos) // found , as decimal separator, so change to .
+        att_value.replace(idx, 1, ".");
+    params.push_back("out_voltage" + std::to_string(chan) + "_hardwaregain=" + att_value);
 
 
     device_source_impl::set_params(this->phy, params);
diff --git a/gr-iio/lib/fmcomms2_source_impl.cc b/gr-iio/lib/fmcomms2_source_impl.cc
index 23bf34d28..934206e5f 100644
--- a/gr-iio/lib/fmcomms2_source_impl.cc
+++ b/gr-iio/lib/fmcomms2_source_impl.cc
@@ -220,10 +220,12 @@ void fmcomms2_source_impl::set_gain(size_t chan, double gain_value)
     std::vector<std::string> params;
 
     if (d_gain_mode[chan].compare("manual") == 0) {
-        // params.push_back("in_voltage" + std::to_string(chan) +
-        //                  "_gain_control_mode=" + d_gain_mode[chan]);
+        std::string gain_string = std::to_string(gain_value);
+        std::string::size_type idx = gain_string.find(',');
+        if (idx != std::string::npos) // found , as decimal separator, so change to .
+            gain_string.replace(idx, 1, ".");
         params.push_back("in_voltage" + std::to_string(chan) +
-                         "_hardwaregain=" + std::to_string(gain_value));
+                         "_hardwaregain=" + gain_string);
     }
     device_source_impl::set_params(params);
     d_gain_value[chan] = gain_value;