At the API level, both '/' and '\' have been accepted since sub-directories were added to DOS. It was only ever at the UI (command prompt), and in how some pro

At the API level, both '/' and '\' have been accepted since sub-directories were added to DOS. It was only ever at the UI (command prompt), and in how some programs converted inputs and outputs where '\' was necessary, as the knowledge about '/' being usable wasn't all that widespread. What used to peeve me was C source on DOS development environments with lines like: #include "path\\to\\file.h" When the following always seemed to work (with the compilers I used): #include "path/to/file.h" Or at least it did with Borland compilers.