To install cpp-argparse-dev, run the following command in macOS terminal (Applications->Utilities->Terminal)
sudo port install cpp-argparse-dev
To see what files were installed by cpp-argparse-dev, run:
port contents cpp-argparse-dev
To later upgrade cpp-argparse-dev, run:
sudo port selfupdate && sudo port upgrade cpp-argparse-dev
Reporting an issue on MacPorts Trac
The MacPorts Project uses a system called Trac to file tickets to report bugs and enhancement requests.
Though anyone may search Trac for tickets, you must have a GitHub account in order to login to Trac to create tickets.