The CN_REALLOCPSZ notification code is sent after direct editing of container text is complete. It notifies the application that the container is about to copy the changed text to the application's text string. This allows the application to ensure that the correct amount of memory is allocated to accommodate the change.

If TRUE is returned by the application, the container control copies the new text to the application's text string. However, if the application returns FALSE, changed text is disregarded.

Warning: Once your application receives the CN_REALLOCPSZ notification code, it must not send any messages to the container until it receives the CN_ENDEDIT notification code, which indicates that direct editing of container text has ended. If any messages are sent to the container before your application receives the CN_ENDEDIT notification code, the results of direct editing are unpredictable.