Question

I deployed an CGI DLL built with Delphi 2007 on the Windows 2008 server. Internally I need to use the current DLL path.

Normally I can use GetModuleFileName or GetModuleName, but on the server they both return:

\\?\c:\my\correct\path

Why the first 4 characters? It looks like a network path? Is there any way to exclude those first 4 characters?

Answer 1

The pertinent documentation is this:

Maximum Path Length Limitation

In the Windows API (with some exceptions discussed in the following
paragraphs), 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. For example, the
maximum path on drive D is “D:\some 256-character path string”
where “” represents the invisible terminating null character for
the current system codepage. (The characters < > are used here for
visual clarity and cannot be part of a valid path string.)

Note File I/O functions in the Windows API convert “/” to “\” as part
of converting the name to an NT-style name, except when using the
“\\?\” prefix as detailed in the following sections.

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. This type of path is composed of components
separated by backslashes, each up to the value returned in the
lpMaximumComponentLength parameter of the GetVolumeInformation
function (this value is commonly 255 characters). To specify an
extended-length path, use the “\\?\” prefix. For example, “\\?\D:\very
long path”.

Note The maximum path of 32,767 characters is approximate, because
the “\\?\” prefix may be expanded to a longer string by the system at
run time, and this expansion applies to the total length.

The “\\?\” prefix can also be used with paths constructed according to
the universal naming convention (UNC). To specify such a path using
UNC, use the “\\?\UNC\” prefix. For example, “\\?\UNC\server\share”,
where “server” is the name of the computer and “share” is the name of
the shared folder. 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, or double dots to represent the parent directory.
Because you cannot use the “\\?\” prefix with a relative path,
relative paths are always limited to a total of MAX_PATH characters.

As long as you are calling Unicode versions of Windows API functions, then there’s no need to strip the "\\?\" prefix. Because the path that you have been handed is a valid path.

As we discovered in the comments, you were calling an ANSI version of an API function. And when you do that, the "\\?\" prefix is not valid. So, stick to Unicode API functions and it’s all good!