I am using Delphi 2010 and my program wants to get the system's temp path. I am using TPath.GetTempPath and everything is working fine... at least for me and my coworkers. But on some customer machines this method returns a cropped path which is (of course) not existing. I found out that the problem seems to be the result from underlying call to GetLongPathName().
The complete code looks like this:
[...]
var
TmpDir : String;
Len : Integer;
begin
[... Call to GetTempPath succeeds and we have a valid temp directory in short "~" notation in var TmpDir ...]
Len := GetLongPathName(PChar(TmpDir), nil, 0); // Len = 37
SetLength(TmpDir, Len - 1); // We want to set the len of TmpDir to 37 - 1.
GetLongPathName(PChar(TmpDir), PChar(TmpDir), Len); // Only 32 (instead of 36) characters are copied - so we have a cropped path - But why?!
end;
[...]
This only happens on some systems and I don't know why. I found a nasty workaround for this, but I would like to know what's going on here.
Can somebody put some light on this?
There is a note about this Windows API function on the Homeland Security pages:
"The return buffer for GetLongPathName() and similar functions might return a truncated path and lead to hard-to-find errors."
https://buildsecurityin.us-cert.gov/bsi-rules/home/g1/753-BSI.html
If you have the source code, you could check if the problem described in this article exists in the Delphi 2010 implementation.