如何判断一个文件属性是否为只读？

[abcynic]

我现在的方法是:

WIN32_FIND_DATA wfd;
FindFirstFile(FileName,&wfd);
if(FILE_ATTRIBUTE_READONLY == wfd.dwFileAttributes)
{
//Do My duty
}

我的程序中FindFirstFile已经成功了，wfd.cFileName也有正确的文件名，但是if语句没有成功，而我所检查的文件确实是只读属性。查MSDN WIN32_FIND_DATA的dwFileAttributes值应该是多个attribute的组合，所以用"=="来判断可能有问题。不知道应该怎样判断，请高手指点。

[wuxuan]

GetFileAttributes
The GetFileAttributes function retrieves attributes for a specified file or directory.

This function retrieves a set of FAT-style attribute information. The GetFileAttributesEx function can obtain other sets of file or directory attribute information.

DWORD GetFileAttributes(
LPCTSTR lpFileName // name of file or directory
);
Parameters
lpFileName
[in] Pointer to a null-terminated string that specifies the name of a file or directory.
Windows NT/2000/XP: In the ANSI version of this function, the name is limited to MAX_PATH characters. To extend this limit to nearly 32,000 wide characters, call the Unicode version of the function and prepend "\\?\" to the path. For more information, see File Name Conventions.

Windows 95/98/Me: This string must not exceed MAX_PATH characters.

Return Values
If the function succeeds, the return value contains the attributes of the specified file or directory.

If the function fails, the return value is INVALID_FILE_ATTRIBUTES. To get extended error information, call GetLastError.

The attributes can be one or more of the following values.

Attribute Meaning
FILE_ATTRIBUTE_ARCHIVE The file or directory is an archive file or directory. Applications use this attribute to mark files for backup or removal.
FILE_ATTRIBUTE_COMPRESSED The file or directory is compressed. For a file, this means that all of the data in the file is compressed. For a directory, this means that compression is the default for newly created files and subdirectories.
FILE_ATTRIBUTE_DEVICE Reserved; do not use.
FILE_ATTRIBUTE_DIRECTORY The handle identifies a directory.
FILE_ATTRIBUTE_ENCRYPTED The file or directory is encrypted. For a file, this means that all data streams in the file are encrypted. For a directory, this means that encryption is the default for newly created files and subdirectories.
FILE_ATTRIBUTE_HIDDEN The file or directory is hidden. It is not included in an ordinary directory listing.
FILE_ATTRIBUTE_NORMAL The file or directory has no other attributes set. This attribute is valid only if used alone.
FILE_ATTRIBUTE_NOT_CONTENT_INDEXED The file will not be indexed by the content indexing service.
FILE_ATTRIBUTE_OFFLINE The data of the file is not immediately available. This attribute indicates that the file data has been physically moved to offline storage. This attribute is used by Remote Storage, the hierarchical storage management software. Applications should not arbitrarily change this attribute.
FILE_ATTRIBUTE_READONLY The file or directory is read-only. Applications can read the file but cannot write to it or delete it. In the case of a directory, applications cannot delete it.
FILE_ATTRIBUTE_REPARSE_POINT The file has an associated reparse point.
FILE_ATTRIBUTE_SPARSE_FILE The file is a sparse file.
FILE_ATTRIBUTE_SYSTEM The file or directory is part of, or is used exclusively by, the operating system.
FILE_ATTRIBUTE_TEMPORARY The file is being used for temporary storage. File systems attempt to keep all of the data in memory for quicker access rather than flushing the data back to mass storage. A temporary file should be deleted by the application as soon as it is no longer needed.

[wuxuan]

你可以使用位操作符呀。

WIN32_FIND_DATA wfd;
FindFirstFile(FileName,&wfd);
if(wfd.dwFileAttributes &FILE_ATTRIBUTE_READONLY == FILE_ATTRIBUTE_READONLY )
{
//Do My duty
}

就可以了。

[duankuanjun]

GetFileAttributes 返回值为FILE_ATTRIBUTE_READONLY

[mfkzj]

GetFileAttributes 返回值为FILE_ATTRIBUTE_READONLY

[qindq]

if((FILE_ATTRIBUTE_READONLY & wfd.dwFileAttributes)==FILE_ATTRIBUTE_READONLY)

[seep]

呵呵，qindq(蜕叟) 已经写出来了
不过我要说的是你的方法肯定有问题