Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Parameter help displays help on the framework's parameters. The parameter accepts an optional argument value. If present, an argument value is interpreted as a parameter name (name guessing works as well, so for example --help=rand displays help on the parameter random). If the parameter name is unknown or ambiguous error is reported. If argument value is absent, a summary of all framework's parameter is displayed.
An optional parameter name string.
--help[=<parameter
name>]