From d0e9d1f383c64b83b9124f96d1ad67e994efe8f9 Mon Sep 17 00:00:00 2001
From: Patrick Valsecchi <patrick@thus.ch>
Date: Tue, 8 Oct 2013 10:32:08 +0200
Subject: [PATCH] Fix edit + cancel = absolute zero

If a temperature in Kelvin is 0, I think we can safely assume it is
not set.

Fixes #207.

Signed-off-by: Patrick Valsecchi <patrick@thus.ch>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
---
 qt-gui.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/qt-gui.cpp b/qt-gui.cpp
index 178ed52af..08eb9d538 100644
--- a/qt-gui.cpp
+++ b/qt-gui.cpp
@@ -269,7 +269,9 @@ QString get_cylinder_used_gas_string(cylinder_t *cyl, bool showunit)
 
 QString get_temperature_string(temperature_t temp, bool showunit)
 {
-	if (prefs.units.temperature == units::CELSIUS) {
+	if (temp.mkelvin == 0) {
+		return "";  //temperature not defined
+	} else if (prefs.units.temperature == units::CELSIUS) {
 		double celsius = mkelvin_to_C(temp.mkelvin);
 		return QString("%1%2%3").arg(celsius, 0, 'f', 1).arg(showunit ? (UTF8_DEGREE): "")
 								.arg(showunit ? tr("C") : "");