What is the difference between deletelater and delete in Qt?

In Qt, both deleteLater and delete are methods used for deleting objects, but they have some differences between them.

1. deleteLater, provided by Qt, is a slot function used to delete an object after the current event loop finishes. This means the object will remain valid until the event loop completes, processing all pending events. Therefore, calling deleteLater in a slot function within the current event loop will delete the object after that slot function completes, without disrupting the current function’s execution. deleteLater is a safe way to delete objects, especially when used in a multi-threaded environment.
2. The keyword delete in C++ is used to immediately delete an object. When delete is called, the object is deleted right away and its memory is released. If there are still pending operations or signal connections on the object, using that object after deletion may result in undefined behavior. Therefore, before using delete, ensure that there are no pointers or references pointing to the object and that all related operations and signal connections have been released.

In conclusion, deleteLater is a safe method for delaying the deletion of an object until the current event loop ends, while delete immediately removes the object.