Doc: harmonize toDouble() and toFloat() for QString and QByteArray

Change-Id: Ic81461899c73c8a68bc3b8bdc1de4be4dd6bdf27
Reviewed-by: Martin Smith <martin.smith@qt.io>

src/corelib/doc/snippets/code/src_corelib_tools_qbytearray.cpp

@@ -353,9 +353,21 @@ long dec = str.toLong(&ok, 10);   // dec == 0, ok == false
 
 //! [38]
 QByteArray string("1234.56");
-double a = string.toDouble();   // a == 1234.56
+bool ok;
+double a = string.toDouble(&ok);   // a == 1234.56, ok == true
+
+string = "1234.56 Volt";
+a = str.toDouble(&ok);             // a == 0, ok == false
 //! [38]
 
+//! [38float]
+QByteArray string("1234.56");
+bool ok;
+double a = string.toFloat(&ok);    // a == 1234.56, ok == true
+
+string = "1234.56 Volt";
+a = str.toFloat(&ok);              // a == 0, ok == false
+//! [38float]
 
 //! [39]
 QByteArray text("Qt is great!");

src/corelib/doc/snippets/qstring/main.cpp

@@ -853,6 +853,8 @@ void Widget::toDoubleFunction()
     double d;
 
     d = QString( "1234.56e-02" ).toDouble(&ok); // ok == true, d == 12.3456
+
+    d = QString( "1234.56e-02 Volt" ).toDouble(&ok); // ok == false, d == 0
     //! [67]
 
     //! [68]
@@ -875,6 +877,9 @@ void Widget::toFloatFunction()
     bool ok;
     QString str2 = "R2D2";
     str2.toFloat(&ok);          // returns 0.0, sets ok to false
+
+    QString str3 = "1234.56 Volt";
+    str3.toFloat(&ok);          // returns 0.0, sets ok to false
     //! [71]
 }
 

src/corelib/tools/qbytearray.cpp

@@ -4124,9 +4124,16 @@ ushort QByteArray::toUShort(bool *ok, int base) const
 
     \snippet code/src_corelib_tools_qbytearray.cpp 38
 
+    \warning The QByteArray content may only contain valid numerical characters
+    which includes the plus/minus sign, the characters g and e used in scientific
+    notation, and the decimal point. Including the unit or additional characters
+    leads to a conversion error.
+
     \note The conversion of the number is performed in the default C locale,
     irrespective of the user's locale.
 
+    This function ignores leading and trailing whitespace.
+
     \sa number()
 */
 
@@ -4150,9 +4157,18 @@ double QByteArray::toDouble(bool *ok) const
     If \a ok is not \c nullptr, failure is reported by setting *\a{ok}
     to \c false, and success by setting *\a{ok} to \c true.
 
+    \snippet code/src_corelib_tools_qbytearray.cpp 38float
+
+    \warning The QByteArray content may only contain valid numerical characters
+    which includes the plus/minus sign, the characters g and e used in scientific
+    notation, and the decimal point. Including the unit or additional characters
+    leads to a conversion error.
+
     \note The conversion of the number is performed in the default C locale,
     irrespective of the user's locale.
 
+    This function ignores leading and trailing whitespace.
+
     \sa number()
 */