gimbal_opaque.h File Reference

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Data Structures
struct	GblOpaqueVTable
struct	GblOpaqueClass

Macros
Type System
Type UUID and cast macros
#define	GBL_OPAQUE_TYPE
#define	GBL_OPAQUE_CLASS(klass)

Typedefs
typedef GBL_RESULT(*	GblOpaqueCopyFn) (void *pOpaque, void **ppNewOpaque)
typedef GBL_RESULT(*	GblOpaqueFreeFn) (void *pOpaque)

Functions
Static Methods
Miscellaenous and Utility methods
GblType	GblOpaque_type (void)
GblType	GblOpaque_register (const char *pName, const GblOpaqueVTable *pVTable)
GblType	GblOpaque_registerRef (const char *pName)
Instance Methods
Methods for dealing with opaque instances (usually handled internally)
GBL_RESULT	GblOpaque_copy (void *pOpaque, GblType type, void **ppNewOpaque)
GBL_RESULT	GblOpaque_free (void *pOpaque, GblType type)

Detailed Description

GblOpaqueClass and API for managing Opaque types.

This file contains the API for registering and managing the lifetime of "opaque" user data types. This is an intermediate libGimbal type, which inherits from GBL_POINTER_TYPE, adding additional functionality. Rather than simple pointer assignments for copy semantics with no lifetime management, a type which derives from GBL_OPAQUE_TYPE adds the bare minimum virtual functions required to implement lifetime management.

When assigning the value of a GBL_OPAQUE_TYPE to another, the "copy" virtual method is called, which may implement value-based copying via something like memcpy(), or reference-based copying via something like incrementing a reference counter.

When the GBL_OPAQUE_TYPE is destroyed, the "free" virtual method is called, which may opt to actually deallocate the object for value-based copied objects OR it may simply decrement a reference counter for reference-based semantics.

Author

2023, 2025 Falco Girgis

Copyright

MIT License

Definition in file gimbal_opaque.h.

Macro Definition Documentation

GBL_OPAQUE_TYPE

#define GBL_OPAQUE_TYPE

Type UUID for GblOpaque.

Definition at line 32 of file gimbal_opaque.h.

GBL_OPAQUE_CLASS

#define GBL_OPAQUE_CLASS

(

klass

)

Function-style GblOpaqueClass cast from GblClass.

Definition at line 33 of file gimbal_opaque.h.

Typedef Documentation

GblOpaqueCopyFn

typedef GBL_RESULT(* GblOpaqueCopyFn) (void *pOpaque, void **ppNewOpaque)

Function signature for for an opaque copy operation, see GblOpaqueVTable::pFnCopy.

Definition at line 39 of file gimbal_opaque.h.

GblOpaqueFreeFn

typedef GBL_RESULT(* GblOpaqueFreeFn) (void *pOpaque)

Function signature for an opaque free operation, see GblOpaqueVTable::pFnFree.

Definition at line 41 of file gimbal_opaque.h.

Function Documentation

GblOpaque_type()

GblType GblOpaque_type

(

void

)

Returns the GblType UUID for GblOpaque.

GblOpaque_register()

GblType GblOpaque_register	(	const char *	pName,
		const GblOpaqueVTable *	pVTable )

Registers a new opaque subtype with the virtual table given by pVTable.

GblOpaque_registerRef()

GblType GblOpaque_registerRef

(

const char *

pName

)

Convenience function which registers a new type meta type which is used with GblRef to manage its lifetime.

GblOpaque_copy()

GBL_RESULT GblOpaque_copy	(	void *	pOpaque,
		GblType	type,
		void **	ppNewOpaque )

Copies an opaque structure with the given type into ppNewOpaque, using its vtable.

GblOpaque_free()

GBL_RESULT GblOpaque_free	(	void *	pOpaque,
		GblType	type )

Frees an opaque structure with the given type using its vtable.