How to create directories in windows with path length greater than 256

I have several level of directories in the folder path. when the path exceeds 256, then I could not create a sub-folder or file 开发者_Go百科from it. Is there any chance to build paths more than this length. Can anyone help me out.

In fact the limit on path strings is 260 characters. The underlying OS, these days, can support much longer path names, up to 32,767 characters. In order to name a path with a long name you need to use the magic \\?\ prefix, and use the Unicode version of the API.

However, many tools don't support such long names. A classic example of such a tool is Explorer which won't let you create objects with names longer than 260 characters. Because of this I strongly advise you to avoid creating such long names—doing so will save you much heartache in the long run.

This should get you started: http://msdn.microsoft.com/en-us/library/aa365247%28v=vs.85%29.aspx#maxpath

Sadly it's an issue that I don't think will be going away any time soon, so you'd do well to familiarize yourself with that stuff.

As an aside, if you have access to robocopy (comes packaged with Windows Vista and 7, but is also available for XP), which supports long paths, you could create your files/subfolders in a higher-up folder and then use robocopy to move the subfolder to its desired location deeper in the folder tree.

According to the documentation here http://msdn.microsoft.com/en-us/library/Aa365247, the maximum length is actually about 32,000, but most windows APIs still limit you to MAX_PATH which is 260. There are some unicode APIs that let you go beyond the 260 limit.

See here, http://msdn.microsoft.com/en-us/library/aa363856.

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.

This is an addendum to the answers above. I extracted only a summary to what I think is relevant, from Microsoft's official documentation:

Maximum Path Length Limitation
In the Windows API (with some exceptions), the maximum length for a path is MAX_PATH, which is defined as 260 characters. A local path is structured in the following order: drive letter, colon, backslash, name components separated by backslashes, and a terminating null character.
Example: "D:\some 256-character-path-string" -> 256

Using long paths
The Windows API has many functions that also have Unicode versions to permit an extended-length path for a maximum total path length of 32,767 characters.
To specify an extended-length path, use the "\?" prefix. For example, "\?\D:\very long path".

Relative paths
Relative paths are always limited to a total of MAX_PATH characters.

Enable Long Paths in Win10
Starting in Windows 10.1607, MAX_PATH limitations have been removed from common Win32 file and directory functions.
However, you must opt-in to the new behavior.

From Microsoft documentation:
https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file?redirectedfrom=MSDN#maximum-path-length-limitation

Warning for Delphi users:
There is a problem in IOUtils. It cannot be used in conjunction with Max_Path. It uses InternalCheckDirPathParam all over the place!

Details: TDirectory.GetDirectoryRoot does not handle correctly paths of Max_Path characters