On 02/02/2026 14:40, Corinna Vinschen via Cygwin wrote:
On Feb 2 13:24, Dan Shelton via Cygwin wrote:
I'm not sure whether the Cygwin code is correct. I did a peek with a
kernel debugger, and I see that FILE_RENAME_INFORMATION.RootDirectory
is always NULL if a file gets renamed to .cyg000000000xxxx. But if I
try that with NTFS or SMB, the NtSetInformationFile() to set
FileRenameInformation always fails.
Your testcase is incorrect, unfortunately.
fri->FileNameLength = (wcslen(dstfile)+1)*sizeof(wchar_t);
For NT file paths, never count the trailing \0 to the length:
fri->FileNameLength = wcslen(dstfile) * sizeof (WCHAR);
With that, your testcase works fine for me.
I am not sure what data structure this supposed "Friday" variable points to,
but in NT low level APIs, such as the NTXxxx syscalls exported by ntdll.dll,
a common structure is the UNICODE_STRING, which has 3 fields:
Pointer to string buffer,
Size of string buffer in bytes (often (length+1) * sizeof(WCHAR)) and
Size of actual string in bytes (not counting the optional term 0 or
other unused buffer space)
Both byte counts are 16 bits, so structure can only hold strings up to
32767 WCHARs.
There are very similar structures using plain char and these structures
can also be marshalled into byte streams by replacing the pointer with a
32 bit byte offset.
Enjoy
Jakob
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Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com
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