PDType

The generic Pajdeg object type. More...

Files
file	PDType.h

Macros
#define	PDReleaseFunc   PDRelease
#define	PDDebugBeginSession()
#define	PDDebugEndSession()   0
#define	PDFlagGlobalObject(ob)

Functions
void	PDRelease (void *pajdegObject)
void *	PDRetain (void *pajdegObject)
void *	PDAutorelease (void *pajdegObject)
PDInstanceType	PDResolve (void *pajdegObject)
const char *	PDDescription (void *pajdegObject)

Detailed Description

The generic Pajdeg object type.

PDType provides the release and retain functionality to Pajdeg objects.

Warning

Not all types in Pajdeg are Pajdeg objects. An object whose type is camel case and begins with capital PD is always a Pajdeg object, and can be retained and released, whereas objects using underscore separation in all lower case are non-Pajdeg objects (used by the Pajdeg system), such as pd_btree. The exception to this is primitive objects, such as PDInteger, PDBool, etc., and PDType itself.

Concept behind Release and Retain

Releasing and retaining is a method for structuring memory management, and is used e.g. in Objective-C and other languages. The concept is fairly straightforward:

• calling a function that contains the word "Create" means you own the resulting object and must at some point release (PDRelease()) or autorelease (PDAutorelease()) it
• retaining an object via PDRetain() means you have to release it at some point
• objects are only valid until the end of the function executing unless they are retained

There are also instances where an object will become invalid in the middle of a function body, if it is released and has no pending autorelease calls.

For example, the following code snippet shows how this works:

The PDPipe object is retained because the function name has the word Create in it, so it must be released.

The PDParser is not retained, as we obtained it through a function whose name did not contain Create – consequently, the parser variable must not be released as we don't own a reference to it.

The meta object must be released by us, as it has the word Create.

Function Documentation

void* PDAutorelease

(

void *

pajdegObject

)

Autorelease a Pajdeg object.

Even if the caller was the last referrer, the object will not be destroyed until the PDPipeExecute() iteration for the current object has ended.

Thus, it is possible to return an object with a zero retain count by autoreleasing it.

Parameters

pajdegObject

The object that should, at some point, be released once.

const char* PDDescription

(

void *

pajdegObject

)

Generate a description of the given object as a C string. The description is generated via the PDInstancePrinters entry for the resolved instance type of the object.

Parameters

pajdegObject

Object whose C string description should be generated

Returns

An "autoreleased" string.

void PDRelease

(

void *

pajdegObject

)

Release a Pajdeg object.

If the caller was the last referrer, the object will be destroyed immediately.

Parameters

pajdegObject

A previously retained or created PD object.

PDInstanceType PDResolve

(

void *

pajdegObject

)

Resolve the PDInstanceType of the given object.

Parameters

pajdegObject

The object whose type should be resolved

Returns

PDInstanceType for the given object

void* PDRetain

(

void *

pajdegObject

)

Retain a Pajdeg object.

Parameters

pajdegObject

A PD object.