- Qt 5.15
- Qt Core
- C++ Classes
- QMetaEnum
- Qt 5.15.18 Reference Documentation

# QMetaEnum Class

The QMetaEnum class provides meta-data about an enumerator. More...

Header: | #include <QMetaEnum>
qmake: | QT += core

- List of all members, including inherited members

## Public Functions

const char * | enumName() const
bool | isFlag() const
bool | isScoped() const
bool | isValid() const
const char * | key(int index) const
int | keyCount() const
int | keyToValue(const char *key, bool *ok = nullptr) const
int | keysToValue(const char *keys, bool *ok = nullptr) const
const char * | name() const
const char * | scope() const
int | value(int index) const
const char * | valueToKey(int value) const
QByteArray | valueToKeys(int value) const

## Static Public Members

QMetaEnum | fromType()

## Detailed Description

Use name() for the enumerator's name. The enumerator's keys (names of each enumerated item) are returned by key(); use keyCount() to find the number of keys. isFlag() returns whether the enumerator is meant to be used as a flag, meaning that its values can be combined using the OR operator.

The conversion functions keyToValue(), valueToKey(), keysToValue(), and valueToKeys() allow conversion between the integer representation of an enumeration or set value and its literal representation. The scope() function returns the class scope this enumerator was declared in.

See also QMetaObject, QMetaMethod, and QMetaProperty.

## 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 as the type name. Non flag enums has the same type and enum names.

Enum names have the same scope as the type name.

This function was introduced in Qt 5.12.

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.

This function was introduced in Qt 5.5.

### 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.

This function was introduced in Qt 5.8.

### 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().

### 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().

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

### 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.

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

### 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().

### int QMetaEnum::value(int index) const

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

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

### const char *QMetaEnum::valueToKey(int 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(int value) const

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

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