Maximum Path Length
In the Windows API, the maximum length for a path is MAX_PATH
, which is defined as 260 characters
. A path is structured in the following order: drive letter, colon, backslash, components separated by backslashes, and a null-terminating character, for example, the maximum path on the D drive is D:\<256 chars>NUL
Note Functions in the Windows API convert "/" to "\" as part of converting the name to an NT style name.
The Unicode versions of several functions permit a maximum path length of approximately 32,000 characters composed of components up to 255 characters in length. To specify that kind of path, use the "\\?\" prefix.
Note The maximum path of 32,000 characters is approximate, because the "\\?\" prefix can be expanded to a longer string, and the expansion applies to the total length.
For example, "\\?\D:\<path>". To specify such a UNC path, use the "\\?\UNC\" prefix. For example, "\\?\UNC\<server>\<share>". These prefixes are not used as part of the path itself. They indicate that the path should be passed to the system with minimal modification, which means that you cannot use forward slashes to represent path separators, or a period to represent the current directory. Also, you cannot use the "\\?\" prefix with a relative path. Relative paths are limited to MAX_PATH characters.
When using the API to create a directory, the specified path cannot be so long that you cannot not append an 8.3 file name.
The shell and the file system may have different requirements. It is possible to create a path with the API that the shell UI cannot handle.