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What do the words "undefined" mean in bullet point §5.19/2.3 in N4140?


What do the words "undefined" mean in bullet point §5.19/2.3 in N4140?

By : dmm
Date : November 14 2020, 04:51 PM
will help you This bullet was added by defect report 699 and it requires that a constexpr function or constructor must be defined before use. The defect report added the following example to 7.1.5 to demonstrate the rule:
code :
constexpr int square(int x);       //OK, declaration
constexpr struct pixel {           // error: pixel is a type
    int x;
    int y;
    constexpr pixel(int);            // OK, declaration
};
constexpr pixel::pixel(int a)
    : x(square(a)), y(square(a)) { } //OK, definition
constexpr pixel small(2);          // error: square not defined, so small(2)
                                     // not constant (5.19 [expr.const]), so constexpr not satisfied
constexpr int square(int x) {      // OK, definition
    return x * x;
}
constexpr pixel large(4);          // OK, square defined


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What's the point of returning an "Undefined Value" when re-defining "print()" function for QScriptEn

What's the point of returning an "Undefined Value" when re-defining "print()" function for QScriptEn


By : user2926438
Date : March 29 2020, 07:55 AM
wish helps you It's not that it is NECESSARY to return undefinedValue(), but when you do, it's the same as not returning anything. Or essentially, as if you declared the function as void print(...), so to speak.
That's what the QtPrintFunction does -- it returns "nothing". But it does have a side effect of appending its argument to the internal data object, whenever you call it. That's why you get all of the values passed to print in the output object.
code :
print("Stack");
print("Overflow");
"garbage";
print("Stack") + '\n' +
print("Overflow");
result = "";
for (i = 0; i < 3; i++)
    result += print(i) + '\n';
QScriptValue myPrintFunction(QScriptContext *context, QScriptEngine *engine)
{
    static QString result;
    for (int i = 0; i < context->argumentCount(); ++i) {
        if (i > 0)
            result.append(" ");
        result.append(context->argument(i).toString());
    }
    result.append('\n');

    return engine->toScriptValue(result);
}
class QTrace: public QObject
{
    ...
    void clear();
    void append(const QString& value);
    const QString& get();
}
QScriptValue myPrintFunction(QScriptContext *context, QScriptEngine *engine)
{
    QString result;
    for (int i = 0; i < context->argumentCount(); ++i) {
        if (i > 0)
            result.append(" ");
        result.append(context->argument(i).toString());
    }
    result.append('\n');

    QScriptValue calleeData = context->callee().data();
    QTrace *trace = qobject_cast<QTrace*>(calleeData.toQObject());
    trace->append(result);

    return engine->undefinedValue();
}
trace->clear();

QScriptValue result = engine->evaluate(command);
if(result.isError())
    output->append(result.toString());
else
    output->append(trace->get());
I'm having some difficulty interpreting bullet point (5.2.1.1) in paragraph §8.5.3/5 of N4140

I'm having some difficulty interpreting bullet point (5.2.1.1) in paragraph §8.5.3/5 of N4140


By : Benjo
Date : March 29 2020, 07:55 AM
this will help
the initializer expression is an lvalue and int is reference-compatible with int (or with int& - I don't know for sure which one I should use here).
code :
using ft = void();
void f();
ft&  l();
ft&& r();
ft*  p();

// function lvalue expressions:
f
l()
r()
*p()
template<typename T>
void move_and_do(T& t)
{
    T&& r = static_cast<T&&>(t); // as if moved
}

int i = 42;
move_and_do(i);

move_and_do(f);
I believe the phrase "not previously declared to have external linkage" is superfluous, in §3.5/3 bullet point

I believe the phrase "not previously declared to have external linkage" is superfluous, in §3.5/3 bullet point


By : Sandipan Karmaker
Date : March 29 2020, 07:55 AM
wish of those help §3.5[basic.link]/3 (my emphasis): , That's easy:
code :
extern const int i; // typically in header file
const int i = 0; // typically in source file
What does the Standard mean by "user-defined conversions are not considered", in bullet point (5.2.2.1) in par

What does the Standard mean by "user-defined conversions are not considered", in bullet point (5.2.2.1) in par


By : Capsluck
Date : March 29 2020, 07:55 AM
With these it helps This was an addendum to the standard to address an issue with the discarding of cv-qualifiers through indirect reference binding of a class with user-defined conversions.
The pertinent defect is 1571.
code :
class A {
public:
  operator volatile int &();
};
A a;

const int & ir1a = a.operator volatile int&(); // error!
const int & ir2a = a; // allowed! ir = a.operator volatile int&();
VBA Method for Indentation "Special Hanging"... spacing between bullet point and text

VBA Method for Indentation "Special Hanging"... spacing between bullet point and text


By : user2789427
Date : March 29 2020, 07:55 AM
seems to work fine Ended up just recording a macro to see what was being changed. Not the most intuitive thing:
code :
With .Cell(r, c)
    .Range.Shading.BackgroundPatternColor = RGB(255, 255, 153)
    .Range.ListFormat.ApplyBulletDefault
    .Range.ParagraphFormat.FirstLineIndent = InchesToPoints(-0.1) 'was this line here
    .Range.ParagraphFormat.LeftIndent = InchesToPoints(0.1)
End With
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