how to quickly verify the case sensitive filename really exists

Question

I have to make a unix compatible windows delphi routine that confirms if a file name exists in filesystem exactly in same CaSe as wanted, e.g. "John.txt" is there, not "john.txt".

If I check "FileExists('john.txt')" its always true for John.txt and JOHN.TXT due windows .

How can I create "FileExistsCaseSensitive(myfile)" function to confirm a file is really what its supposed to be.

DELPHI Sysutils.FileExists uses the following function to see if file is there, how to change it to double check file name is on file system is lowercase and exists:

function FileAge(const FileName: string): Integer;
var
  Handle: THandle;
  FindData: TWin32FindData;
  LocalFileTime: TFileTime;
begin
  Handle := FindFirstFile(PChar(FileName), FindData);
  if Handle <> INVALID_HANDLE_VALUE then
  begin
    Windows.FindClose(Handle);
    if (FindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY) = 0 then
    begin
      FileTimeToLocalFileTime(FindData.ftLastWriteTime, LocalFileTime);
      if FileTimeToDosDateTime(LocalFileTime, LongRec(Result).Hi,
        LongRec(Result).Lo) then Exit;
    end;
  end;
  Result := -1;
end;

Answer 1

function FileExistsEx(const FileName: string): Integer;
var
  Handle: THandle;
  FindData: TWin32FindData;
  LocalFileTime: TFileTime;
begin
  Handle := FindFirstFile(PChar(FileName), FindData);
  if Handle <> INVALID_HANDLE_VALUE then
  begin
    Windows.FindClose(Handle);
    if (FindData.dwFileAttributes and FILE_ATTRIBUTE_DIRECTORY) = 0 then
    begin
      FileTimeToLocalFileTime(FindData.ftLastWriteTime, LocalFileTime);
      if FileTimeToDosDateTime(LocalFileTime, LongRec(Result).Hi, LongRec(Result).Lo) then
        if AnsiSameStr(FindData.cFileName, ExtractFileName(FileName)) then Exit;
    end;
  end;
  Result := -1;
end;

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Tom, I'm also intrigued by your use case. I tend to agree with Motti that it would be counter intuitive and might strike your users as odd.