CopyFileW function (winbase.h)
Copies an existing file to a new file.
The CopyFileEx function provides two additional capabilities. CopyFileEx can call a specified callback function each time a portion of the copy operation is completed, and CopyFileEx can be canceled during the copy operation.
To perform this operation as a transacted operation, use the CopyFileTransacted function.
Syntax
BOOL CopyFileW(
[in] LPCWSTR lpExistingFileName,
[in] LPCWSTR lpNewFileName,
[in] BOOL bFailIfExists
);
Parameters
[in] lpExistingFileName
The name of an existing file.
By default, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, prepend "\\?\" to the path. For more information, see Naming Files, Paths, and Namespaces.
Tip
Starting with Windows 10, Version 1607, you can opt-in to remove the MAX_PATH limitation without prepending "\\?\". See the "Maximum Path Length Limitation" section of Naming Files, Paths, and Namespaces for details.
If lpExistingFileName does not exist, CopyFile fails, and GetLastError returns ERROR_FILE_NOT_FOUND.
[in] lpNewFileName
The name of the new file.
By default, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, prepend "\\?\" to the path. For more information, see Naming Files, Paths, and Namespaces.
Tip
Starting with Windows 10, Version 1607, you can opt-in to remove the MAX_PATH limitation without prepending "\\?\". See the "Maximum Path Length Limitation" section of Naming Files, Paths, and Namespaces for details.
[in] bFailIfExists
If this parameter is TRUE and the new file specified by lpNewFileName already exists, the function fails. If this parameter is FALSE and the new file already exists, the function overwrites the existing file and succeeds.
Return value
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Remarks
The security resource properties (ATTRIBUTE_SECURITY_INFORMATION) for the existing file are copied to the new file.
Windows 7, Windows Server 2008 R2, Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP: Security resource properties for the existing file are not copied to the new file until Windows 8 and Windows Server 2012.
File attributes for the existing file are copied to the new file. For example, if an existing file has the FILE_ATTRIBUTE_READONLY file attribute, a copy created through a call to CopyFile will also have the FILE_ATTRIBUTE_READONLY file attribute. For more information, see Retrieving and Changing File Attributes.
This function fails with ERROR_ACCESS_DENIED if the destination file already exists and has the FILE_ATTRIBUTE_HIDDEN or FILE_ATTRIBUTE_READONLY attribute set.
When CopyFile is used to copy an encrypted file, it attempts to encrypt the destination file with the keys used in the encryption of the source file. If this cannot be done, this function attempts to encrypt the destination file with default keys. If neither of these methods can be done, CopyFile fails with an ERROR_ENCRYPTION_FAILED error code.
Symbolic link behavior—If the source file is a symbolic link, the actual file copied is the target of the symbolic link.
If the destination file already exists and is a symbolic link, the target of the symbolic link is overwritten by the source file.
In Windows 8 and Windows Server 2012, this function is supported by the following technologies.
| Technology | Supported |
|---|---|
| Server Message Block (SMB) 3.0 protocol | Yes |
| SMB 3.0 Transparent Failover (TFO) | Yes |
| SMB 3.0 with Scale-out File Shares (SO) | Yes |
| Cluster Shared Volume File System (CsvFS) | Yes |
| Resilient File System (ReFS) | Yes |
Examples
For an example, see Retrieving and Changing File Attributes.
Note
The winbase.h header defines CopyFile as an alias that automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that is not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows XP [desktop apps | UWP apps] |
| Minimum supported server | Windows Server 2003 [desktop apps | UWP apps] |
| Target Platform | Windows |
| Header | winbase.h (include Windows.h) |
| Library | Kernel32.lib |
| DLL | Kernel32.dll |