QLatin1StringView Class

 if (str == "auto" || str == "extern"
         || str == "static" || str == "register") {
     ...
 }

 if (str == QString("auto") || str == QString("extern")
         || str == QString("static") || str == QString("register")) {
     ...
 }

 str.append("Hello ").append("World");

 if (str == "auto"_L1
         || str == "extern"_L1
         || str == "static"_L1
         || str == "register"_L1 {
     ...
 }

 QLabel *label = new QLabel("MOD"_L1, this);

Member Function Documentation

Compares this string view with UTF-16 string view str, Latin-1 string view l1, or the character ch, respectively. Returns a negative integer if this string is less than str, l1 or ch, returns a positive integer if it is greater than str, l1 or ch, and zero if they are equal.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

See also operator==(), operator<(), and operator>().

Returns true if this Latin-1 string view starts with the UTF-16 string viewed by str, the Latin-1 string viewed by l1, or the character ch, respectively; otherwise returns false.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

See also endsWith().

Returns true if this Latin-1 string view ends with the UTF-16 string viewed str, the Latin-1 string viewed by l1, or the character ch, respectively; otherwise returns false.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

See also startsWith().

Returns the index position in this Latin-1 string view of the first occurrence of the UTF-16 string viewed by str, the Latin-1 string viewed by l1, or the character ch, respectively, searching forward from index position from. Returns -1 if str, l1 or c is not found, respectively.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

If from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.

See also QString::indexOf().

Returns true if this Latin-1 string view contains an occurrence of the UTF-16 string viewed by str, the Latin-1 string viewed by l1, or the character ch, respectively; otherwise returns false.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

See also indexOf(), QStringView::contains(), QStringView::indexOf(), and QString::indexOf().

Returns the index position in this Latin-1 string view of the last occurrence of the UTF-16 string viewed by str, the Latin-1 string viewed by l1, or the character ch, respectively, searching backward from index position from; returns -1 if str, l1 or ch is not found, respectively.

If from is -1, the search starts at the last character; if it is -2, at the next to last character and so on.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

See also indexOf(), QStringView::lastIndexOf(), QStringView::indexOf(), and QString::indexOf().

This function overloads lastIndexOf().

Returns the index position in this Latin-1 string view of the last occurrence of the UTF-16 string viewed by str or the Latin-1 string viewed by l1, respectively. Returns -1 if str or l1 is not found, respectively.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

This function was introduced in Qt 6.2.

Returns the number of (potentially overlapping) occurrences of the UTF-16 string viewed by str, the Latin-1 string viewed by l1, or the character ch, respectively, in this string view.

If cs is Qt::CaseSensitive (the default), the search is case-sensitive; otherwise the search is case-insensitive.

This function was introduced in Qt 6.4.

See also contains() and indexOf().

Returns this QLatin1StringView converted to a corresponding numeric value using base base, which is ten by default. Bases 0 and 2 through 36 are supported, using letters for digits beyond 9; A is ten, B is eleven and so on.

If base is 0, the base is determined automatically using the following rules (in this order), if the Latin-1 string view begins with:

• "0x", the rest of it is read as hexadecimal (base 16)
• "0b", the rest of it is read as binary (base 2)
• "0", the rest of it is read as octal (base 8)
• otherwise it is read as decimal

Returns 0 if the conversion fails.

If ok is not nullptr, failure is reported by setting *ok to false, and success by setting *ok to true.

This function ignores leading and trailing spacing characters.

This function was introduced in Qt 6.4.

Returns this QLatin1StringView converted to a corresponding floating-point value.

Returns an infinity if the conversion overflows or 0.0 if the conversion fails for other reasons (e.g. underflow).

If ok is not nullptr, failure is reported by setting *ok to false, and success by setting *ok to true.

This function ignores leading and trailing spacing characters.

This function was introduced in Qt 6.4.

template <typename... Args> QString QLatin1StringView::arg(Args &&... args) const

Replaces occurrences of %N in this string with the corresponding argument from args. The arguments are not positional: the first of the args replaces the %N with the lowest N (all of them), the second of the args the %N with the next-lowest N etc.

Args can consist of anything that implicitly converts to QString, QStringView or QLatin1StringView.

In addition, the following types are also supported: QChar, QLatin1Char.

See also QString::arg().

[constexpr noexcept(...), since 6.0] template <typename Needle, typename... Flags> decltype(qTokenize(*this, std::forward<Needle>(needle), flags...)) QLatin1StringView::tokenize(Needle &&sep, Flags... flags) const

Splits the string into substring views wherever sep occurs, and returns a lazy sequence of those strings.

Equivalent to

 return QStringTokenizer{std::forward<Needle>(sep), flags...};

except it works without C++17 Class Template Argument Deduction (CTAD) enabled in the compiler.

See QStringTokenizer for how sep and flags interact to form the result.

 QStringTokenizer result = sv.tokenize(sep);

(without template arguments). If you can't use C++17 CTAD, you must store the return value only in auto variables:

 auto result = sv.tokenize(sep);

This is because the template arguments of QStringTokenizer have a very subtle dependency on the specific tokenize() overload from which they are returned, and they don't usually correspond to the type used for the separator.

This function was introduced in Qt 6.0.

See also QStringTokenizer and qTokenize().

[constexpr noexcept] QLatin1StringView::QLatin1StringView()

Constructs a QLatin1StringView object that stores a nullptr.

See also data(), isEmpty(), isNull(), and Distinction Between Null and Empty Strings.

[constexpr noexcept, since 6.4] QLatin1StringView::QLatin1StringView(std::nullptr_t)

Constructs a QLatin1StringView object that stores a nullptr.

This function was introduced in Qt 6.4.

See also data(), isEmpty(), isNull(), and Distinction Between Null and Empty Strings.

[explicit constexpr noexcept] QLatin1StringView::QLatin1StringView(const char *str)

Constructs a QLatin1StringView object that stores str.

The string data is not copied. The caller must be able to guarantee that str will not be deleted or modified as long as the QLatin1StringView object exists.

See also latin1().

[constexpr] QLatin1StringView::QLatin1StringView(const char *first, const char *last)

Constructs a QLatin1StringView object that stores first with length (last - first).

The range [first,last) must remain valid for the lifetime of this Latin-1 string object.

Passing nullptr as first is safe if last is nullptr, too, and results in a null Latin-1 string.

The behavior is undefined if last precedes first, first is nullptr and last is not, or if last - first > INT_MAX.

[constexpr noexcept] QLatin1StringView::QLatin1StringView(const char *str, qsizetype size)

Constructs a QLatin1StringView object that stores str with size.

The string data is not copied. The caller must be able to guarantee that str will not be deleted or modified as long as the QLatin1StringView object exists.

See also latin1().

[explicit noexcept] QLatin1StringView::QLatin1StringView(const QByteArray &str)

Constructs a QLatin1StringView object as a view on str.

The string data is not copied. The caller must be able to guarantee that str will not be deleted or modified as long as the QLatin1StringView object exists.

See also latin1().

[explicit constexpr noexcept, since 6.3] QLatin1StringView::QLatin1StringView(QByteArrayView str)

Constructs a QLatin1StringView object as a view on str.

The string data is not copied. The caller must be able to guarantee that the data which str is pointing to will not be deleted or modified as long as the QLatin1StringView object exists. The size is obtained from str as-is, without checking for a null-terminator.

This function was introduced in Qt 6.3.

See also latin1().

[constexpr] QLatin1Char QLatin1StringView::at(qsizetype pos) const

Returns the character at position pos in this object.

See also operator[]().

[constexpr] QLatin1Char QLatin1StringView::back() const

Returns the last character in the string. Same as at(size() - 1).

This function is provided for STL compatibility.

See also front(), at(), and operator[]().

[constexpr noexcept] QLatin1StringView::const_iterator QLatin1StringView::begin() const

Returns a const STL-style iterator pointing to the first character in the string.

This function is provided for STL compatibility.

See also end(), cbegin(), rbegin(), and data().

[constexpr noexcept] QLatin1StringView::const_iterator QLatin1StringView::cbegin() const

Same as begin().

This function is provided for STL compatibility.

See also cend(), begin(), crbegin(), and data().

[constexpr noexcept] QLatin1StringView::const_iterator QLatin1StringView::cend() const

Same as end().

This function is provided for STL compatibility.

See also cbegin(), end(), and crend().

[constexpr] void QLatin1StringView::chop(qsizetype length)

Truncates this string by length characters.

Same as *this = left(size() - length).

See also sliced(), first(), last(), chopped(), and truncate().

[constexpr] QLatin1StringView QLatin1StringView::chopped(qsizetype length) const

Returns the substring of length size() - length starting at the beginning of this object.

Same as left(size() - length).

See also sliced(), first(), last(), chop(), and truncate().

[noexcept, since 6.5] int QLatin1StringView::compare(QUtf8StringView str, Qt::CaseSensitivity cs = Qt::CaseSensitive) const

Compares this string view with str and returns a negative integer if this string view is less than str, a positive integer if it is greater than str, and zero if they are equal.

If cs is Qt::CaseSensitive (the default), the comparison is case-sensitive; otherwise the comparison is case-insensitive.

This function was introduced in Qt 6.5.

See also operator==(), operator<(), and operator>().

[constexpr noexcept, since 6.4] const char *QLatin1StringView::constBegin() const

Same as begin().

This function is provided for compatibility with other Qt containers.

This function was introduced in Qt 6.4.

See also constEnd(), begin(), cbegin(), and data().

[constexpr noexcept, since 6.4] const char *QLatin1StringView::constData() const

Returns the start of the Latin-1 string referenced by this object.

This function is provided for compatibility with other Qt containers.

This function was introduced in Qt 6.4.

See also data().

[constexpr noexcept, since 6.4] const char *QLatin1StringView::constEnd() const

Same as end().

This function is provided for compatibility with other Qt containers.

This function was introduced in Qt 6.4.

See also constBegin(), end(), cend(), and crend().

[noexcept] QLatin1StringView::const_reverse_iterator QLatin1StringView::crbegin() const

Same as rbegin().

This function is provided for STL compatibility.

See also crend(), rbegin(), and cbegin().

[noexcept] QLatin1StringView::const_reverse_iterator QLatin1StringView::crend() const

Same as rend().

This function is provided for STL compatibility.

See also crbegin(), rend(), and cend().

[constexpr noexcept] const char *QLatin1StringView::data() const

Returns the start of the Latin-1 string referenced by this object.

[constexpr noexcept, since 6.4] bool QLatin1StringView::empty() const

Returns whether the Latin-1 string referenced by this object is empty (size() == 0) or not.

This function is provided for STL compatibility.

This function was introduced in Qt 6.4.

See also isEmpty(), isNull(), and size().

[constexpr noexcept] QLatin1StringView::const_iterator QLatin1StringView::end() const

Returns a const STL-style iterator pointing just after the last character in the string.

This function is provided for STL compatibility.

See also begin(), cend(), and rend().

[constexpr, since 6.4] QLatin1Char QLatin1StringView::first() const

Returns the first character in the string. Same as at(0) or front().

This function is provided for compatibility with other Qt containers.

This function was introduced in Qt 6.4.

See also last(), front(), and back().

[constexpr, since 6.0] QLatin1StringView QLatin1StringView::first(qsizetype n) const

Returns a Latin-1 string view that contains the first n characters of this string view.

This function was introduced in Qt 6.0.

See also last(), startsWith(), chopped(), chop(), and truncate().

[constexpr] QLatin1Char QLatin1StringView::front() const

Returns the first character in the string. Same as at(0).

This function is provided for STL compatibility.

See also back(), at(), and operator[]().

[constexpr noexcept] bool QLatin1StringView::isEmpty() const

Returns whether the Latin-1 string referenced by this object is empty (size() == 0) or not.

See also isNull() and size().

[constexpr noexcept] bool QLatin1StringView::isNull() const

Returns whether the Latin-1 string referenced by this object is null (data() == nullptr) or not.

See also isEmpty() and data().

[constexpr, since 6.4] QLatin1Char QLatin1StringView::last() const

Returns the last character in the string. Same as at(size() - 1) or back().

This function is provided for compatibility with other Qt containers.

This function was introduced in Qt 6.4.

See also first(), back(), and front().

[constexpr, since 6.0] QLatin1StringView QLatin1StringView::last(qsizetype n) const

Returns a Latin-1 string view that contains the last n characters of this string view.

This function was introduced in Qt 6.0.

See also first(), endsWith(), chopped(), chop(), and truncate().

[noexcept, since 6.3] qsizetype QLatin1StringView::lastIndexOf(QChar ch, Qt::CaseSensitivity cs = Qt::CaseSensitive) const

This is an overloaded function.

This function was introduced in Qt 6.3.

[constexpr noexcept] const char *QLatin1StringView::latin1() const

Returns the start of the Latin-1 string referenced by this object.

[constexpr] QLatin1StringView QLatin1StringView::left(qsizetype length) const

If you know that length cannot be out of bounds, use first() instead in new code, because it is faster.

Returns the substring of length length starting at position 0 in this Latin-1 string view.

The entire Latin-1 string view is returned if length is greater than or equal to size(), or less than zero.

See also first(), last(), sliced(), startsWith(), chopped(), chop(), and truncate().

[constexpr noexcept, since 6.4] qsizetype QLatin1StringView::length() const

Same as size().

This function is provided for compatibility with other Qt containers.

This function was introduced in Qt 6.4.

[constexpr] QLatin1StringView QLatin1StringView::mid(qsizetype start, qsizetype length = -1) const

Returns the substring of length length starting at position start in this Latin-1 string view.

If you know that start and length cannot be out of bounds, use sliced() instead in new code, because it is faster.

Returns an empty Latin-1 string view if start exceeds the length of this string view. If there are less than length characters available in this string view starting at start, or if length is negative (default), the function returns all characters that are available from start.

See also first(), last(), sliced(), chopped(), chop(), and truncate().

[noexcept] QLatin1StringView::const_reverse_iterator QLatin1StringView::rbegin() const

Returns a const STL-style reverse iterator pointing to the first character in the string, in reverse order.

This function is provided for STL compatibility.

See also rend(), crbegin(), and begin().

[noexcept] QLatin1StringView::const_reverse_iterator QLatin1StringView::rend() const

Returns a STL-style reverse iterator pointing just after the last character in the string, in reverse order.

This function is provided for STL compatibility.

See also rbegin(), crend(), and end().

[constexpr] QLatin1StringView QLatin1StringView::right(qsizetype length) const

If you know that length cannot be out of bounds, use last() instead in new code, because it is faster.

Returns the substring of length length starting at position size() - length in this Latin-1 string view.

The entire Latin-1 string view is returned if length is greater than or equal to size(), or less than zero.

See also first(), last(), sliced(), endsWith(), chopped(), chop(), and truncate().

[constexpr noexcept] qsizetype QLatin1StringView::size() const

Returns the size of the Latin-1 string referenced by this object.

[constexpr, since 6.0] QLatin1StringView QLatin1StringView::sliced(qsizetype pos) const

Returns a Latin-1 string view starting at position pos in this string view, and extending to its end.

This function was introduced in Qt 6.0.

See also first(), last(), chopped(), chop(), and truncate().

[constexpr, since 6.0] QLatin1StringView QLatin1StringView::sliced(qsizetype pos, qsizetype n) const

Returns a Latin-1 string view that points to n characters of this string view, starting at position pos.

This function was introduced in Qt 6.0.

See also first(), last(), chopped(), chop(), and truncate().

[since 6.0] QString QLatin1StringView::toString() const

Converts this Latin-1 string into a QString. Equivalent to

 return QString(*this);

This function was introduced in Qt 6.0.

[noexcept] QLatin1StringView QLatin1StringView::trimmed() const

Strips leading and trailing whitespace and returns the result.

Whitespace means any character for which QChar::isSpace() returns true. This includes the ASCII characters '\t', '\n', '\v', '\f', '\r', and ' '.

[constexpr] void QLatin1StringView::truncate(qsizetype length)

Truncates this string to length length.

Same as *this = left(length).

See also sliced(), first(), last(), chopped(), and chop().

bool QLatin1StringView::operator!=(const char *other) const

Returns true if this string is not equal to const char pointer other; otherwise returns false.

The other const char pointer is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

See also Comparing Strings.

bool QLatin1StringView::operator!=(const QByteArray &other) const

This function overloads operator!=().

The other byte array is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

bool QLatin1StringView::operator<(const char *other) const

Returns true if this string is lexically less than const char pointer other; otherwise returns false.

The other const char pointer is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

See also Comparing Strings.

bool QLatin1StringView::operator<(const QByteArray &other) const

This is an overloaded function.

The other byte array is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

bool QLatin1StringView::operator<=(const char *other) const

Returns true if this string is lexically less than or equal to const char pointer other; otherwise returns false.

The other const char pointer is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

See also Comparing Strings.

bool QLatin1StringView::operator<=(const QByteArray &other) const

This is an overloaded function.

The other byte array is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

bool QLatin1StringView::operator==(const char *other) const

Returns true if the string is equal to const char pointer other; otherwise returns false.

The other const char pointer is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

See also Comparing Strings.

bool QLatin1StringView::operator==(const QByteArray &other) const

This is an overloaded function.

The other byte array is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

bool QLatin1StringView::operator>(const char *other) const

Returns true if this string is lexically greater than const char pointer other; otherwise returns false.

The other const char pointer is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

See also Comparing Strings.

bool QLatin1StringView::operator>(const QByteArray &other) const

This is an overloaded function.

The other byte array is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

bool QLatin1StringView::operator>=(const char *other) const

Returns true if this string is lexically greater than or equal to const char pointer other; otherwise returns false.

The other const char pointer is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

See also Comparing Strings.

bool QLatin1StringView::operator>=(const QByteArray &other) const

This is an overloaded function.

The other byte array is converted to a QString using the QString::fromUtf8() function.

You can disable this operator by defining QT_NO_CAST_FROM_ASCII when you compile your applications. This can be useful if you want to ensure that all user-visible strings go through QObject::tr(), for example.

[constexpr] QLatin1Char QLatin1StringView::operator[](qsizetype pos) const

Returns the character at position pos in this object.

See also at().

 using namespace Qt::Literals::StringLiterals;

 auto str = "hello"_L1;