set_summary

Description:

[ Version ( since = "2.12" ) ]
public void set_summary (string summary)

Adds a string to be displayed in `--help` output before the list of options.

This is typically a summary of the program functionality.

Note that the summary is translated (see set_translate_func and set_translation_domain).

this	a OptionContext
summary	a string to be shown in `--help` output before the list of options, or null