VC method to determine a file as a directory

2020-04-02 02:54:12
OfStack

The example of this article tells the VC to determine a file as a directory method, to share with you for your reference. The specific implementation method is as follows:

This is a custom function to determine whether a file is a directory:

/**

 * check whether a file is a directory

 @return true if is a directory, else false(if file not exists, false)

 */

__declspec(dllexport) bool IsDirectory(const char* filename)

{

 

  DWORD dwAttr = ::GetFileAttributes(filename);  //Gets the file property 

 

  if (dwAttr == 0xFFFFFFFF)    //The file or directory does not exist 

    return false;

  else if (dwAttr&FILE_ATTRIBUTE_DIRECTORY)  //If the directory is 

    return true; 

  else

    return false;

}

The following is the GetFileAttribute definition from MSDN:

Retrieves a set of FAT file system attributes for a specified file or directory

The Parameters

lpFileName

The name of The file or directory.In The ANSI version of this function, The name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, Call the Unicode version of the function and prepend "//? /" to the path. For more information, see Naming a File. The maximum length is the maximum length of the file name of the system. If you are in a unicode environment, you need to call the unicode version of this function.

The Return Value

If the function succeeds, the return value contains the attributes of the specified file or directory.
If the function succeeds, the return value will contain the following file properties:
If the function fails, the return value is INVALID_FILE_ATTRIBUTES. To get extended error information, call GetLastError.
If the function fails, the return value is INVALID_FILE_ATTRIBUTES. You can get more detailed error information through GetLastError
The attributes can be one or more of The following values.
A file property can be a combination of one or more of the following values.

Return code/value	Description
FILE_ATTRIBUTE_ARCHIVE 32 0x20	A file or directory that is an archive file or directory. Applications use this attribute to mark files for backup or removal. Archive file
FILE_ATTRIBUTE_COMPRESSED 2048 0x800	A file or directory that is compressed. For a file, all of the data in the file is compressed. For a directory, compression is the default for newly created files and subdirectories. The compressed file
FILE_ATTRIBUTE_DEVICE 64 0x40	Reserved; do not use.
FILE_ATTRIBUTE_DIRECTORY 16 0x10	The handle that identifies a directory. Directory file
FILE_ATTRIBUTE_ENCRYPTED 16384 0x4000	A file or directory that is encrypted. For a file, all data streams in the file are encrypted. For a directory, encryption is the default for newly created files and subdirectories. Encrypted file
FILE_ATTRIBUTE_HIDDEN 2 0x2	The file or directory is hidden. It is not included in an ordinary directory listing. Hidden files
FILE_ATTRIBUTE_NORMAL 128 0x80	A file or directory that does not have other attributes set. This attribute is valid only when used alone.
FILE_ATTRIBUTE_NOT_CONTENT_INDEXED 8192 0x2000	The file is not to be indexed by the content indexing service.
FILE_ATTRIBUTE_OFFLINE 4096 0x1000	The data of a file is not available immediately. This attribute indicates that the file data is physically moved to offline storage. This attribute is used by Remote Storage, which is the hierarchical storage management software. Applications should not arbitrarily change this attribute.
FILE_ATTRIBUTE_READONLY 1 0x1	A file or directory that is read-only. For a file, applications can read the file, but cannot write to it or delete it. For a directory, applications cannot delete it.
FILE_ATTRIBUTE_REPARSE_POINT 1024 0x400	A file or directory that has an associated reparse point, or a file that is a symbolic link.
FILE_ATTRIBUTE_SPARSE_FILE 512 0x200	A file that is a sparse file.
FILE_ATTRIBUTE_SYSTEM 4 0x4	A file or directory that the operating system uses a part of, or uses exclusively.
FILE_ATTRIBUTE_TEMPORARY 256 0x100	A file that is being used for temporary storage. File systems avoid writing data back to mass storage if sufficient cache memory is available, because typically, an application deletes a temporary file after the handle is closed. In that scenario, the system can entirely avoid writing the data. Otherwise, the data is written after the handle is closed.
FILE_ATTRIBUTE_VIRTUAL 65536 0x10000	A file is a virtual file.

Hope that this article described the VC programming for you to help.