QMetaProperty

QMetaProperty is a class in Qt’s meta-object system that describes a single property declared with the Q_PROPERTY macro in a QObject-derived class. It provides both metadata about the property and runtime access to its value, enabling dynamic introspection and manipulation of objects.

A QMetaProperty exposes key information such as the property's name, its type (via type() for the type id and typeName() for a human-readable name), and the capabilities of the property. Typical capability checks include isReadable(), isWritable(), and isResettable(), which indicate whether the property can be read, written, or reset to a default value. If the property has a notify signal, QMetaProperty can provide access to that signal through a notify mechanism, allowing bindings and observers to react to changes.

For value access, QMetaProperty offers read() to obtain the current value from a given QObject, and write() to assign a new value, using QVariant to handle the value in a type-safe, generic way. This enables generic code to interact with properties without hard-coded accessors.

QMetaProperty is accessed via a class’s QMetaObject, typically through methods like property() or propertyCount(). It is often used in scenarios such as model/view bindings, serialization, scripting, and debugging, where runtime property information is advantageous. In combination with QMetaEnum and related meta-object facilities, QMetaProperty supports working with enumerations and other complex property types.

Overall, QMetaProperty provides a lightweight, runtime-friendly descriptor for Qt properties, balancing introspection with performance by leveraging compile-time metadata exposed through the meta-object system.