On Win32 systems, there should be no trailing slash character after the directory name, but the drive letter must be followed by a colon and a forward slash (:/). On Linux/UNIX systems, a trailing slash after the directory name will not cause problems.
Oops I overlooked that... creating my sources in Linux, and after that running in Windows, but never looking into the manual again because it is working in Linux, right? ;-)
Anyway, this situation causes the code to be less portable. So in a Win32 situation, you always have to explicitly add a "/" between the directoryname and the filename if you want to concatenate them. In Unix this is not necessary.
<Sigh>
In the end it has something to do with the C API of course, which is different in Win32 compared to Unix, but from user-experience-point-of-view, it is a little bit uncomfortable... but I'll if-then-else around it....