path: root/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
diff options
authorEdward Welbourne <>2019-09-05 17:50:17 +0200
committerEdward Welbourne <>2019-09-30 20:05:42 +0200
commit4bd6cd1992fdcdc933861ba646ea9da870670237 (patch)
tree55940f60c88352427f55f215d9970dbbbe97c174 /tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
parent86876744f07cbaa01daca6869b896741878c39a3 (diff)
Featurize support for signaling NaN
One of our compilers for emscripten coerces all signaling NaNs to quiet ones, so won't do any actual signaling. Anyone relying on them to do so shall be disappointed, so it's better that they know about it at compile-time - or, at least, have the ability to find it out. Put the signaling NaN producers (and remaining (test) code using them) under the control of a feature that's disabled when numeric_limits claims double has no signaling NaN. Assume the bootstrap library doesn't need signaling NaNs. Sadly, until C++20 <bit>, there's no contexpr way to test that alleged signalling and quiet NaNs are actually distinct. Added some auto-tests for signaling NaN, including that it's distinct from quiet NaN. Any platform on which the last fails should disable this feature. Task-number: QTBUG-77967 Change-Id: I57e9d14bfe276732cd313887adc9acc354d88f08 Reviewed-by: Joerg Bornemann <>
Diffstat (limited to 'tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp')
1 files changed, 15 insertions, 0 deletions
diff --git a/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp b/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
index 5697d21547..a6d600e125 100644
--- a/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
+++ b/tests/auto/corelib/global/qnumeric/tst_qnumeric.cpp
@@ -44,6 +44,9 @@ private slots:
void fuzzyCompare();
void rawNaN_data();
void rawNaN();
+#if QT_CONFIG(signaling_nan)
+ void distinctNaN();
void generalNaN_data();
void generalNaN();
void infinity();
@@ -139,6 +142,9 @@ void tst_QNumeric::rawNaN_data()
QTest::newRow("quiet") << qQNaN();
+#if QT_CONFIG(signaling_nan)
+ QTest::newRow("signaling") << qSNaN();
void tst_QNumeric::rawNaN()
@@ -147,6 +153,15 @@ void tst_QNumeric::rawNaN()
+#if QT_CONFIG(signaling_nan)
+void tst_QNumeric::distinctNaN()
+ const double qnan = qQNaN();
+ const double snan = qSNaN();
+ QVERIFY(memcmp(&qnan, &snan, sizeof(double)) != 0);
void tst_QNumeric::generalNaN_data()