Detect platform to choose delimiter to use for reading options from command line

[anonymous]

POSIX systems usually use - or -- as a "delimiter" when reading options from command lines. For e.g. the 'ls' program on a linux system:

  ls --help
  ....
  -a, --all                  do not ignore entries starting with .
  -A, --almost-all           do not list implied . and ..
      --author               with -l, print the author of each file
  -b, --escape               print octal escapes for nongraphic 
 characters
      --block-size=SIZE      use SIZE-byte blocks
      --help                 print this
  ....

Windows usually uses the / character instead, for e.g. for dir: dir /?: Typically, the '/' is the delimiter.

  ...
  /B          Uses bare format (no heading information or summary).
  ...

It would be useful to have the library recognize the platform on which it is begin compiled (or even better, the platform being targeted) and use the default for that platform for reading options from the command line.

[Sascha Ochsenknecht]

Hi,

I'm not so much familiar with other style than Linux/POSIX.

In program_options/parsers.hpp is a style enum defined, the default is set to unix_style which is:

        unix_style = (allow_short | short_allow_adjacent | short_allow_next
                      | allow_long | long_allow_adjacent | long_allow_next
                      | allow_sticky | allow_guessing 
                      | allow_dash_for_short)

How would it look like for Windows (ar long options allowed for windows....)? What other style's do we have (MacOS, ...) ?

Thanks, Sascha

[anonymous]

can the user actually change this default library-wide ? without changing the library source code of course.

[Sascha Ochsenknecht]

It is an optional parameter of e.g. parse_command_line(): http://www.boost.org/doc/libs/1_41_0/doc/html/boost/program_options/parse_command_line.html

If you pass a user defined styl;e, then this is used instead of default_style (which is actually unix_style).