QMetaEnum Class

Member Function Documentation

const char *QMetaEnum::enumName() const

Returns the enum name of the flag (without the scope).

For example, the Qt::AlignmentFlag flag has AlignmentFlag as the enum name, but Alignment as the type name. Non flag enums has the same type and enum names.

Enum names have the same scope as the type name.

See also isValid() and name().

[static] template <typename T> QMetaEnum QMetaEnum::fromType()

Returns the QMetaEnum corresponding to the type in the template parameter. The enum needs to be declared with Q_ENUM.

[since 6.9] bool QMetaEnum::is64Bit() const

Returns true if the underlying type of this enumeration is 64 bits wide.

This function was introduced in Qt 6.9.

See also value64().

bool QMetaEnum::isFlag() const

Returns true if this enumerator is used as a flag; otherwise returns false.

When used as flags, enumerators can be combined using the OR operator.

See also keysToValue() and valueToKeys().

bool QMetaEnum::isScoped() const

Returns true if this enumerator is declared as a C++11 enum class; otherwise returns false.

bool QMetaEnum::isValid() const

Returns true if this enum is valid (has a name); otherwise returns false.

See also name().

const char *QMetaEnum::key(int index) const

Returns the key with the given index, or nullptr if no such key exists.

See also keyCount(), value(), and valueToKey().

int QMetaEnum::keyCount() const

Returns the number of keys.

See also key().

[since 6.9] std::optional<quint64> QMetaEnum::keyToValue64(const char *key) const

Returns the integer value of the given enumeration key, or std::nullopt if key is not defined.

For flag types, use keysToValue64().

This function always sign-extends the value of 32-bit enumerations to 64 bits, if their underlying type is signed (e.g., int, short). In most cases, this is the expected behavior.

A notable exception is for flag values that have bit 31 set, like 0x8000'0000, because some compilers (such as Microsoft Visual Studio), do not automatically switch to an unsigned underlying type. To avoid this problem, explicitly specify the underlying type in the enum declaration.

This function was introduced in Qt 6.9.

See also valueToKey(), isFlag(), and keysToValue64().

int QMetaEnum::keyToValue(const char *key, bool *ok = nullptr) const

Returns the integer value of the given enumeration key, or -1 if key is not defined.

If key is not defined, *ok is set to false; otherwise *ok is set to true.

For flag types, use keysToValue().

If this is a 64-bit enumeration (see is64Bit()), this function returns the low 32-bit portion of the value. Use keyToValue64() to obtain the full value instead.

See also keyToValue64, valueToKey(), isFlag(), keysToValue(), and is64Bit().

std::optional<quint64> QMetaEnum::keysToValue64(const char *keys) const

Returns the value derived from combining together the values of the keys using the OR operator, or std::nullopt if keys is not defined. Note that the strings in keys must be '|'-separated.

This function always sign-extends the value of 32-bit enumerations to 64 bits, if their underlying type is signed (e.g., int, short). In most cases, this is the expected behavior.

A notable exception is for flag values that have bit 31 set, like 0x8000'0000, because some compilers (such as Microsoft Visual Studio), do not automatically switch to an unsigned underlying type. To avoid this problem, explicitly specify the underlying type in the enum declaration.

See also isFlag(), valueToKey(), and valueToKeys().

int QMetaEnum::keysToValue(const char *keys, bool *ok = nullptr) const

Returns the value derived from combining together the values of the keys using the OR operator, or -1 if keys is not defined. Note that the strings in keys must be '|'-separated.

If keys is not defined, *ok is set to false; otherwise *ok is set to true.

If this is a 64-bit enumeration (see is64Bit()), this function returns the low 32-bit portion of the value. Use keyToValue64() to obtain the full value instead.

See also keysToValue64(), isFlag(), valueToKey(), valueToKeys(), and is64Bit().

[since 6.6] QMetaType QMetaEnum::metaType() const

Returns the meta type of the enum.

If the QMetaObject that this enum is part of was generated with Qt 6.5 or earlier, this will be an invalid meta type.

This function was introduced in Qt 6.6.

const char *QMetaEnum::name() const

Returns the name of the type (without the scope).

For example, the Qt::Key enumeration has Key as the type name and Qt as the scope.

For flags this returns the name of the flag type, not the name of the enum type.

See also isValid(), scope(), and enumName().

const char *QMetaEnum::scope() const

Returns the scope this enumerator was declared in.

For example, the Qt::AlignmentFlag enumeration has Qt as the scope and AlignmentFlag as the name.

See also name().

[since 6.9] std::optional<quint64> QMetaEnum::value64(int index) const

Returns the value with the given index if it exists; or returns a std::nullopt if it doesn't.

This function always sign-extends the value of 32-bit enumerations to 64 bits, if their underlying type is signed (e.g., int, short). In most cases, this is the expected behavior.

A notable exception is for flag values that have bit 31 set, like 0x8000'0000, because some compilers (such as Microsoft Visual Studio), do not automatically switch to an unsigned underlying type. To avoid this problem, explicitly specify the underlying type in the enum declaration.

This function was introduced in Qt 6.9.

See also keyCount(), key(), keyToValue(), and is64Bit().

int QMetaEnum::value(int index) const

Returns the value with the given index; or returns -1 if there is no such value.

If this is an enumeration with a 64-bit underlying type (see is64Bit()), this function returns the low 32-bit portion of the value. Use value64() to obtain the full value instead.

See also value64(), keyCount(), key(), and keyToValue().

const char *QMetaEnum::valueToKey(quint64 value) const

Returns the string that is used as the name of the given enumeration value, or nullptr if value is not defined.

For flag types, use valueToKeys().

See also isFlag() and valueToKeys().

QByteArray QMetaEnum::valueToKeys(quint64 value) const

Returns a byte array of '|'-separated keys that represents the given value.

See also isFlag(), valueToKey(), and keysToValue().