qputenv: port to QByteArrayView

The vast majority of in-tree users pass simple and short C string
literals as the value. By porting to QByteArrayView, we document that
we'll accept non-NUL-terminated data, and do the NUL-termination
internally, using SSO'ed std::string, saving memory allocations in the
common case of short strings.

I didn't bother to check which direction std::string takes for
nullptrs these days (there was a change accepted in that area for
C++20 or 23), so play it safe and protect against them.

Follow-up to

Task-number: QTBUG-105302
Change-Id: I2369acc62f1d5cbc26135396cfe0602d8c75300c
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp b/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp
index f221c9db90..2196724f41 100644
--- a/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp
+++ b/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp
@@ -270,7 +270,7 @@ void tst_QHighDpi::screenDpiChange()
 void tst_QHighDpi::environment_QT_SCALE_FACTOR()
 {
     qreal factor = 3.1415;
-    qputenv("QT_SCALE_FACTOR", QByteArray::number(factor));
+    qputenv("QT_SCALE_FACTOR", std::to_string(factor));
 
     QList<qreal> dpiValues { 96, 144, 192 };
     std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));