`addprop` — Add a per-instance dynamic property to a handle object.

prop = addprop(obj, name) adds a dynamic property to a valid dynamicprops handle object and returns a matlab.metadata.DynamicProperty metadata handle for that per-instance property.

Syntax

prop = addprop(object, property_name)

Inputs

Name	Type	Required	Default	Description
`object`	`Any`	Yes	—	Scalar handle object that receives a per-instance dynamic property.
`property_name`	`PropertyName`	Yes	—	Name of the dynamic property to add.

Returns

Name	Type	Description
`prop`	`Any`	Dynamic property metadata handle.

Errors

Identifier	When	Message
`RunMat:dynamicprops:InvalidTarget`	The target is not a valid handle object.	`dynamicprops: target must be a valid handle object`
`RunMat:dynamicprops:InvalidName`	The property name is empty or not a valid identifier.	`dynamicprops: invalid property name`
`RunMat:dynamicprops:DuplicateProperty`	A class-defined or dynamic property already exists with the requested name.	`dynamicprops: property already exists`
`RunMat:dynamicprops:InvalidMetadata`	A dynamic property metadata handle is invalid or malformed.	`dynamicprops: invalid dynamic property metadata`
`RunMat:dynamicprops:UnsupportedMetadataProperty`	A metadata property assignment uses an unsupported property name or value.	`dynamicprops: unsupported dynamic property metadata assignment`

How `addprop` works

The target must be a valid handle object whose class inherits from dynamicprops; value objects, ordinary handle classes, and structs are rejected.
The property name must be a valid identifier and must not duplicate a class-defined property or an existing dynamic property on the same instance.
The new property is immediately readable and writable through dot syntax, getfield, and setfield.
The returned metadata handle exposes Name, DefiningClass, GetAccess, SetAccess, Dependent, Hidden, Transient, NonCopyable, AbortSet, SetObservable, GetObservable, and Description fields.
Writable metadata fields update the target object's dynamic property metadata. Name and DefiningClass are read-only.
delete(prop) removes the dynamic property and invalidates the metadata handle.

GPU memory and residency

addprop mutates host-side object metadata. GPU-resident numeric values assigned into dynamic properties follow the same residency behavior as ordinary object properties.

Examples

Add and use a dynamic property

classdef Sensor < dynamicprops
end
s = new_object('Sensor');
p = addprop(s, 'gain');
s.gain = 7;
value = s.gain

Expected output:

value = 7

Set metadata

p = addprop(s, 'label');
p.Hidden = true;
tf = p.Hidden

Expected output:

tf = logical(1)

Using `addprop` with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how addprop changes the result.

Run a small addprop example, explain the result, then change one input and compare the output.

FAQ

Does addprop work on value classes?⌄

No. MATLAB dynamic properties are handle-object instance state, so RunMat requires a valid handle object.

Are dynamic properties saved to MAT files?⌄

Not as full classdef metadata. RunMat saves object property values through the existing object serialization path, but complete dynamic-property persistence requires broader classdef persistence support.

Do SetObservable and GetObservable fire property listeners?⌄

The metadata flags are stored and reported, but full observable-property listener semantics are not implemented yet.

class · clear · clearAllMemoizedCaches · clearCache · clearvars · dbclear · dbstack · dbstatus · dbtype · evalc · findprop · getcallinfo · inputParser · isa · ischar · isdeployed · iskeyword · ismethod · isobject · isstring · isUnderlyingType · keyboard · matlab.metadata.DynamicProperty.delete · memoize · metaclass · mislocked · mlock · munlock · namelengthmax · onCleanup · stats · superclasses · underlyingType · verLessThan · version · which · who · whos

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how addprop is executed, line by line, in Rust.

View the source for addprop in Rust on GitHub
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Found a bug? Open an issue with a minimal reproduction.

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addprop — Add a per-instance dynamic property to a handle object.