GetLongPathNameW function (fileapi.h)
Converts the specified path to its long form.
To perform this operation as a transacted operation, use the GetLongPathNameTransacted function.
For more information about file and path names, see Naming Files, Paths, and Namespaces.
To use this function, the caller must have the following permissions on the specified path and parent directories:
- List Folder
- Read Data
- Read Attributes
DWORD GetLongPathNameW( [in] LPCWSTR lpszShortPath, [out] LPWSTR lpszLongPath, [in] DWORD cchBuffer );
The path to be converted.
In the ANSI version of this function, GetLongPathNameA, the name is limited to MAX_PATH (260) characters. To extend this limit to 32,767 wide characters, call the Unicode version of the function, GetLongPathNameW, and prepend "\\?\" to the path. For more information, see Naming Files, Paths, and Namespaces.
A pointer to the buffer to receive the long path.
You can use the same buffer you used for the lpszShortPath parameter.
The size of the buffer lpszLongPath points to, in TCHARs.
If the function succeeds, the return value is the length, in TCHARs, of the string copied to lpszLongPath, not including the terminating null character.
If the lpBuffer buffer is too small to contain the path, the return value is the size, in TCHARs, of the buffer that is required to hold the path and the terminating null character.
If the function fails for any other reason, such as if the file does not exist, the return value is zero. To get extended error information, call GetLastError.
On many file systems, a short file name contains a tilde (~) character. However, not all file systems follow this convention. Therefore, do not assume that you can skip calling GetLongPathName if the path does not contain a tilde (~) character.
If the file or directory exists but a long path is not found, GetLongPathName succeeds, having copied the string referred to by the lpszShortPath parameter to the buffer referred to by the lpszLongPath parameter.
If the return value is greater than the value specified in cchBuffer, you can call the function again with a buffer that is large enough to hold the path. For an example of this case, see the Example Code section for GetFullPathName.
In Windows 8 and Windows Server 2012, this function is supported by the following technologies.
|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|
For an example that uses GetLongPathName, see the Example Code section for GetFullPathName.
The fileapi.h header defines GetLongPathName as an alias which 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 not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
|Minimum supported client||Windows XP [desktop apps | UWP apps]|
|Minimum supported server||Windows Server 2003 [desktop apps | UWP apps]|
|Header||fileapi.h (include Windows.h)|