- 1 year ago
Why is CopyFileEx blocking even though the callback reports all bytes have been copied
If the CopyFileEx
function in C++ is blocking even though the callback reports that all bytes have been copied, there could be a few possible reasons for this behavior:
Callback implementation: Ensure that your callback function is correctly implemented and returning the correct values. The
CopyProgressRoutine
callback function should returnPROGRESS_CONTINUE
if the copy operation should continue, andPROGRESS_STOP
if it should stop. If the callback function is not returningPROGRESS_CONTINUE
after reporting that all bytes have been copied, theCopyFileEx
function might interpret it as a stop signal and block.Synchronous copy mode: By default,
CopyFileEx
operates in synchronous mode, meaning it blocks until the entire file is copied. If you want to perform an asynchronous copy, you need to specify theCOPY_FILE_ASYNC
flag in thedwCopyFlags
parameter. Without this flag, the function will complete the copy operation before returning.Copy destination: Check if the destination file or directory is causing the blocking behavior. If the destination file is locked or being accessed by another process, it could prevent
CopyFileEx
from completing the copy operation. Ensure that the destination file is accessible and not being used by any other application.Antivirus or security software: Some antivirus or security software can interfere with file operations and cause unexpected blocking behavior. Temporarily disable any such software to see if it resolves the issue. If the problem is resolved, you may need to configure the antivirus or security software to allow the
CopyFileEx
operation.Operating system limitations: Depending on the operating system and file system, there may be certain limitations on file copying operations. For example, if the destination file system does not support the size or attributes of the source file, it can cause blocking behavior. Ensure that the source and destination file systems are compatible and support the necessary file attributes.
If none of the above suggestions resolve the issue, providing more specific details about your code and the environment you're working in could help in further troubleshooting.