Data Structures
struct	ObjClassInfo

struct	ClassSet

struct	ObjInst

struct	ObjInst_WeakRef

Macros
#define	objClassInfoName(cname) cname##_clsinfo

#define	Weak(clsname) clsname##_WeakRef

#define	ObjInst(inst) ((ObjInst*)(unused_noeval(&((inst)->_is_ObjInst)), (inst)))

#define	ObjInst_WeakRef(ref) ((ObjInst_WeakRef*)(unused_noeval(&((ref)->_is_ObjInst_WeakRef)), (ref)))

#define	objInstBase(inst) ObjInst(inst)

#define	objWeakRefBase(ref) ObjInst_WeakRef(ref)

#define	objClsInfo(inst) (inst->_clsinfo)

#define	objAcquire(inst) (_objAcquire(objInstBase(inst)), (inst))

#define	objRelease(pinst) (unused_noeval(&(((pinst))->_is_ObjInst)), _objRelease((ObjInst*)(pinst)))

#define	objClassIf(clsname, ifname) ((ifname*)_objClassIf(&objClassInfoName(clsname), objIfBase(&objIfTmplName(ifname))))

#define	objInstIf(inst, ifname) ((ifname*)_objInstIf(objInstBase(inst), objIfBase(&objIfTmplName(ifname))))

#define	objGetWeak(clsname, inst) ((Weak(clsname))_objGetWeak((ObjInst)clsname(inst)))

#define	objCloneWeak(ref) (_objCloneWeak(objWeakRefBase(ref)))

#define	objDestroyWeak(pref) (unused_noeval(&(((pref))->_is_ObjInst_WeakRef)), _objDestroyWeak((ObjInst_WeakRef*)(pref)))

#define	objAcquireFromWeak(clsname, ref) ((clsname)_objAcquireFromWeak((ObjInst_WeakRef)Weak(clsname)(ref)))

#define	objDynCast(clsname, inst) ((clsname*)_objDynCast(objInstBase(inst), &objClassInfoName(clsname)))

#define	objAcquireFromWeakDyn(clsname, ref) ((clsname*)_objAcquireFromWeakDyn(objWeakRefBase(ref), &objClassInfoName(clsname)))

Typedefs
typedef struct ObjClassInfo	ObjClassInfo

typedef struct ObjInst	ObjInst

typedef struct ClassSet	ClassSet

typedef struct ObjInst_WeakRef	ObjInst_WeakRef

Functions
ObjClassInfo *	classSetFind (const ClassSet *cs, strref name)

void	_objDestroy (ObjInst *inst)

Detailed Description

Classes are the concrete types in the object system that store per-instance data and implement interfaces. Each class has associated runtime metadata (ObjClassInfo) that describes its structure, inheritance relationships, and interface implementations.

Classes support:

Single implementation inheritance (one parent class)
Multiple interface implementation
Reference-counted memory management
Runtime type information and dynamic casting
Optional initialization and destruction callbacks

Classes are defined in .cxh files and the build system generates the boilerplate code.

Macro Definition Documentation

◆ objAcquire

#define objAcquire ( inst ) (_objAcquire(objInstBase(inst)), (inst))

ClassType *objAcquire(ClassType *inst)

Increment the reference count of an object

Use this when storing an additional reference to an object. Each objAcquire() must be paired with a corresponding objRelease(). Does nothing if inst is NULL.

Example:

Document *doc = documentCreate(_SL("Title"));  // refcount = 1
Document *doc2 = objAcquire(doc);           // refcount = 2
objRelease(&doc);                           // refcount = 1
objRelease(&doc2);                          // refcount = 0, object destroyed

Parameters

inst	Pointer to object instance (may be NULL)

Returns: The same pointer passed in (for convenience)

Definition at line 234 of file objclass.h.

◆ objAcquireFromWeak

#define objAcquireFromWeak	(	clsname,
		ref
	)	((clsname)_objAcquireFromWeak((ObjInst_WeakRef)Weak(clsname)(ref)))

ClassName *objAcquireFromWeak(ClassName, Weak(ClassName) *ref)

Attempt to acquire the object referenced by a weak reference

If the object still exists, increments its reference count and returns it. If the object has been destroyed, returns NULL. The caller is responsible for calling objRelease() on the returned object.

Example:

Weak(Document) *weak = objGetWeak(Document, doc);
// ... later, possibly after doc was released ...
Document *doc2 = objAcquireFromWeak(Document, weak);
if (doc2) {
    // Object still exists
    objRelease(&doc2);
}

Parameters

clsname	Class name for type casting
ref	Weak reference (may be NULL)

Returns: Object pointer with incremented refcount, or NULL if object was destroyed

Definition at line 366 of file objclass.h.

◆ objAcquireFromWeakDyn

#define objAcquireFromWeakDyn	(	clsname,
		ref
	)	((clsname*)_objAcquireFromWeakDyn(objWeakRefBase(ref), &objClassInfoName(clsname)))

ClassName *objAcquireFromWeakDyn(ClassName, Weak(BaseClass) *ref)

Acquire from weak reference with runtime type checking

Combines objAcquireFromWeak() and objDynCast(). Attempts to acquire the object and verify it's compatible with the requested class type. Returns NULL if the object was destroyed or is not compatible with the target class.

Parameters

clsname	Class name to cast to
ref	Weak reference (may be NULL)

Returns: Object cast to requested type with incremented refcount, or NULL

Definition at line 405 of file objclass.h.

◆ objClassIf

#define objClassIf	(	clsname,
		ifname
	)	((ifname*)_objClassIf(&objClassInfoName(clsname), objIfBase(&objIfTmplName(ifname))))

InterfaceType *objClassIf(ClassName, InterfaceName)

Get interface implementation from a class (without instance)

Queries whether a class implements a specific interface and returns the populated interface structure if it does. Useful for accessing interface methods when you don't have an instance.

Parameters

clsname	Class name (e.g., Document)
ifname	Interface name (e.g., Printable)

Returns: Pointer to populated interface, or NULL if class doesn't implement it

Definition at line 272 of file objclass.h.

◆ objClassInfoName

#define objClassInfoName ( cname ) cname##_clsinfo

Construct class info variable name from class name

Parameters

cname Class name

Returns: Expands to the class info variable name (e.g., Document_clsinfo)

Definition at line 96 of file objclass.h.

◆ objCloneWeak

#define objCloneWeak ( ref ) (_objCloneWeak(objWeakRefBase(ref)))

WeakRefType *objCloneWeak(WeakRefType *ref)

Increment the reference count of a weak reference

Creates an additional reference to the same weak reference object. Each objCloneWeak() must be paired with objDestroyWeak().

Parameters

ref	Weak reference to clone (may be NULL)

Returns: The same weak reference with incremented refcount

Definition at line 322 of file objclass.h.

◆ objClsInfo

#define objClsInfo ( inst ) (inst->_clsinfo)

ObjClassInfo *objClsInfo(ClassType *inst)

Get the class metadata for an object instance

Parameters

inst	Pointer to any class instance

Returns: Pointer to the class's ObjClassInfo structure

Definition at line 203 of file objclass.h.

◆ objDestroyWeak

#define objDestroyWeak ( pref ) (unused_noeval(&((*(pref))->_is_ObjInst_WeakRef)), _objDestroyWeak((ObjInst_WeakRef**)(pref)))

void objDestroyWeak(WeakRefType **pref)

Release a weak reference

Decrements the weak reference's own reference count. When the count reaches zero, the weak reference object itself is destroyed. The pointer is set to NULL.

Example:

Weak(Document) *weak = objGetWeak(Document, doc);
// Use weak reference...
objDestroyWeak(&weak);  // weak is now NULL

Parameters

pref	Pointer to weak reference pointer (automatically set to NULL)

Definition at line 340 of file objclass.h.

◆ objDynCast

#define objDynCast	(	clsname,
		inst
	)	((clsname*)_objDynCast(objInstBase(inst), &objClassInfoName(clsname)))

ClassName *objDynCast(ClassName, ClassType *inst)

Safely cast an object to a different class type with runtime checking

Checks if the object is an instance of the specified class or any of its subclasses. Returns the object cast to the requested type if compatible, NULL otherwise.

Example:

ObjInst *baseObj = getSomeObject();
Document *doc = objDynCast(Document, baseObj);
if (doc) {
    // Safe to use as Document
}

Parameters

clsname	Class name to cast to
inst	Object instance to cast (may be NULL)

Returns: Object cast to requested type, or NULL if incompatible

Definition at line 389 of file objclass.h.

◆ objGetWeak

#define objGetWeak	(	clsname,
		inst
	)	((Weak(clsname))_objGetWeak((ObjInst)clsname(inst)))

Weak(ClassName) *objGetWeak(ClassName, ClassType *inst)

Get a weak reference to an object

Creates a weak reference if one doesn't exist, or returns the existing weak reference. Weak references allow observing an object without owning it. The returned weak reference has its own reference count and must be destroyed with objDestroyWeak().

Parameters

clsname	Class name for type casting
inst	Object instance

Returns: Weak reference to the object (never NULL)

Definition at line 310 of file objclass.h.

◆ ObjInst

#define ObjInst ( inst ) ((ObjInst*)(unused_noeval(&((inst)->_is_ObjInst)), (inst)))

ObjInst *ObjInst(ClassType *inst)

Cast a class instance pointer to base ObjInst type

Parameters

inst	Pointer to any class instance

Returns: Base ObjInst pointer (with compile-time type validation)

Definition at line 170 of file objclass.h.

◆ ObjInst_WeakRef

#define ObjInst_WeakRef ( ref ) ((ObjInst_WeakRef*)(unused_noeval(&((ref)->_is_ObjInst_WeakRef)), (ref)))

ObjInst_WeakRef *ObjInst_WeakRef(WeakRefType *ref)

Cast a weak reference pointer to base ObjInst_WeakRef type

Parameters

ref	Pointer to any weak reference

Returns: Base ObjInst_WeakRef pointer (with compile-time type validation)

Definition at line 178 of file objclass.h.

◆ objInstBase

#define objInstBase ( inst ) ObjInst(inst)

ObjInst *objInstBase(ClassType *inst)

Alias for ObjInst() cast

Parameters

inst	Pointer to any class instance

Returns: Base ObjInst pointer

Definition at line 187 of file objclass.h.

◆ objInstIf

#define objInstIf	(	inst,
		ifname
	)	((ifname*)_objInstIf(objInstBase(inst), objIfBase(&objIfTmplName(ifname))))

InterfaceType *objInstIf(ClassType *inst, InterfaceName)

Query an object for a specific interface implementation

Returns the populated interface if the object implements it, NULL otherwise. Always check the return value before using the interface to ensure the object supports it.

Example:

ObjInst *obj = getSomeObject();
Printable *printIf = objInstIf(obj, Printable);
if (printIf) {
    printIf->print(obj);
}

Parameters

inst	Object instance (may be NULL)
ifname	Interface name

Returns: Pointer to populated interface, or NULL if not implemented

Definition at line 295 of file objclass.h.

◆ objRelease

#define objRelease ( pinst ) (unused_noeval(&((*(pinst))->_is_ObjInst)), _objRelease((ObjInst**)(pinst)))

void objRelease(ClassType **pinst)

Decrement reference count and destroy object if it reaches zero

This is the primary way to release ownership of an object. The pointer is automatically set to NULL after the call. If the reference count reaches zero, the object's destroy() callback (if any) is called, followed by memory deallocation. Does nothing if *pinst is NULL.

CRITICAL: Pass a pointer-to-pointer, not a pointer. The object pointer will be set to NULL.

Example:

Document *doc = documentCreate(_SL("Title"));
// Use doc...
objRelease(&doc);  // Note: &doc, not doc
// doc is now NULL

Parameters

pinst Pointer to object pointer (automatically set to NULL)

Definition at line 257 of file objclass.h.

◆ objWeakRefBase

#define objWeakRefBase ( ref ) ObjInst_WeakRef(ref)

ObjInst_WeakRef *objWeakRefBase(WeakRefType *ref)

Alias for ObjInst_WeakRef() cast

Parameters

ref	Pointer to any weak reference

Returns: Base ObjInst_WeakRef pointer

Definition at line 195 of file objclass.h.

◆ Weak

#define Weak ( clsname ) clsname##_WeakRef

Construct weak reference type name from class name

Parameters

clsname Class name

Returns: Expands to the weak reference type (e.g., Document_WeakRef)

Definition at line 162 of file objclass.h.

Typedef Documentation

◆ ClassSet

typedef struct ClassSet ClassSet

A named set of classes: the declared vocabulary of a dynamic object slot

This is the class counterpart of StructSet. A member declared object[SomeSet] holds an instance of any class in the set, and the set is what turns the wire name back into a class when the document is read — without the consumer having to register a resolver for it.

cxautogen emits one of these per classset declaration in a .cxh, with the entries sorted by wire name so the lookup is a binary search. Every class in a set must carry a wire name, which means it must be [serialize] or implement Serializable; cxautogen rejects the declaration otherwise, since a class with no name could never be resolved back.

◆ ObjClassInfo

typedef struct ObjClassInfo ObjClassInfo

Runtime metadata for a class

This structure contains all the information needed to manage a class at runtime, including its size, inheritance relationships, interface implementations, and lifecycle callbacks. One instance exists per class for the lifetime of the program.

The structure is divided into two sections:

Static fields: Set by the class implementer during declaration
Runtime fields: Populated automatically during first instantiation

Definition at line 31 of file objclass.h.

◆ ObjInst

typedef struct ObjInst ObjInst

Base structure for all object instances

ObjInst is the implicit base class for all objects in the CX object system. Every class instance begins with these fields, allowing generic handling of objects regardless of their specific class type.

The structure uses a union trick with _is_ObjInst to enable compile-time type checking in macros while maintaining C compatibility.

Definition at line 32 of file objclass.h.

◆ ObjInst_WeakRef

typedef struct ObjInst_WeakRef ObjInst_WeakRef

Weak reference structure

Allows observing an object without owning it. When the object is destroyed, the weak reference's _inst pointer is set to NULL, allowing safe detection of destruction. Multiple weak references can point to the same object.

Function Documentation

◆ _objDestroy()

void _objDestroy ( ObjInst * inst )

Internal object destruction function - DO NOT CALL DIRECTLY!

This function is called internally when an object's reference count reaches zero. Always use objRelease() instead, which properly manages reference counting.

◆ classSetFind()

ObjClassInfo * classSetFind	(	const ClassSet *	cs,
		strref	name
	)

Looks up a class by its wire name in a ClassSet using binary search.

Parameters

cs	The ClassSet to search (must have entries sorted by name)
name	The class name to look up

Returns: Pointer to the matching ObjClassInfo, or NULL if not found

Note that membership is by exact class: a derived class does not satisfy a set that names only its base, because the set is the list of concrete types the slot may hold and reading one back constructs exactly the class the name resolves to.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

◆ objAcquire

◆ objAcquireFromWeak

◆ objAcquireFromWeakDyn

◆ objClassIf

◆ objClassInfoName

◆ objCloneWeak

◆ objClsInfo

◆ objDestroyWeak

◆ objDynCast

◆ objGetWeak

◆ ObjInst

◆ ObjInst_WeakRef

◆ objInstBase

◆ objInstIf

◆ objRelease

◆ objWeakRefBase

◆ Weak

Typedef Documentation

◆ ClassSet

◆ ObjClassInfo

◆ ObjInst

◆ ObjInst_WeakRef

Function Documentation

◆ _objDestroy()

◆ classSetFind()