I've just discovered boost's program_options and at first glance it looked exactly what I was searching for, which was a easy to use library which was capable of handling the command line arguments parsing in a fast and efficient way. Unfortunately one of the things which I had my mind set to was the possibility of defining precedent options. To put it in other words, enable the parser to accept some options only if they were casted in a particular order and complain if that order wasn't respected. For example, accepting something like: app --add --file but complain if the arguments are like: app --file --add or app --add One other thing that I was hoping that boost's program_options was capable of handling was some sort of semantic interpretation according to the option's orders. Take this case for example: app --add --file --remove --file What I was hoping for was that program_options was capable of interpreting the first invocation of --file as relating to --add and the second invocation relating to --remove, instead of intepreting as two distinct invocations of --file. So, is it possible to accomplish that with boost's program_options? If so, could anyone be so kind to provide a simple example? Thanks in advance Rui Maciel -- Running Kubuntu 6.10 with KDE 3.5.5 and proud of it. jabber:rui_maciel@jabber.org