From: Vladimir Prus (ghost_at_[hidden])
Date: 2003-05-07 01:05:59
Neal D. Becker wrote:
> It looks like when setting variables using
> options_description.add_options(), bool variables are set to false if no
> option is actually given, but variables of other types, such as int, are
> not initialized if not given on the command line? This is my understanding
> based on the program behaviour - is this correct?
Yes, this is so. The behaviour is due to code in
parameter_creator<bool>::operator(), in options_description.tcc:211
Two things are done:
- the default value of bool parameters is "0"
- the value when options is present withouth a value (like in "--switch") is
The rationale is that for boolean values default is quite obvious, and test
for boolean option can be as simple as
For ints, there's no such obvious default, so if default value is desired it
should be specified manually.
I've updated the docs to specify the semantics.
> Unsubscribe & other changes:
Boost list run by bdawes at acm.org, gregod at cs.rpi.edu, cpdaniel at pacbell.net, john at johnmaddock.co.uk