CGPDFDocumentRetain

CGPDFDocumentRetain is a function within the Core Graphics framework of Apple's operating systems, including macOS, iOS, watchOS, and tvOS. Its primary purpose is to increase the reference count of a Core Graphics PDF document object. This is a fundamental aspect of memory management in Objective-C and C-based frameworks where reference counting is employed. When a CGPDFDocument object is created or obtained through other Core Graphics functions, it is assigned an initial reference count. Calling CGPDFDocumentRetain on this object increments its reference count by one. This mechanism ensures that the document object remains in memory as long as it is being referenced by one or more parts of the application or system. Conversely, CGPDFDocumentRelease is used to decrement the reference count. When the reference count of a CGPDFDocument object reaches zero, the system automatically deallocates the memory associated with it, preventing memory leaks. Developers must explicitly call CGPDFDocumentRetain when they need to hold onto a CGPDFDocument object beyond its initial scope of ownership or when passing it to another function that will also manage its lifecycle. Proper use of CGPDFDocumentRetain and CGPDFDocumentRelease is crucial for stable and efficient memory management when working with PDF documents in applications.