On Sun, 08 Sep 2013 19:32:23 +0200 Sven Barth <pascaldra...@googlemail.com> wrote:
> On 08.09.2013 14:17, Bart wrote: > > On 9/8/13, Tomas Hajny <xhaj...@hajny.biz> wrote: > > > >> Why do you believe that ExpandFilename is not threadsafe (on Windows or > >> any other platform)? >[...] > > And that is exactly the point. > > GetDir calls GetCurentDirectory and MS says (see: > > http://msdn.microsoft.com/en-us/library/windows/desktop/aa364934%28v=vs.85%29.aspx) > > that multithreaded applications should not call GetCurrentDirectory. > > The problem is not GetCurrentDirectory itself (this function and > SetCurrentDirectory use the process's PEB lock to access the current > directory which is stored inside the PEB as well), but that different > threads could call SetCurrentDirectory with different values and thus a > thread who expected the current directory to be a specific one might > resolve a relative path (by using another WinAPI function) using a > current directory set by a different thread. > > So this can not be solved by using a lock inside ExpandFilename and > might happen on other systems as well as long as the current directory > is not stored per thread. Actually the problem is that Windows has multiple current directories, but you can only read the one of the active drive. For example: Thread 1: ExpandFilename('C:test.pas'); Thread 2: ExpandFilename('B:test.pas'); In order to get the current directory of C: (B:) you have to switch the current drive and switch back. Mattias _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
