OptionContext.setSummary
void setSummary(string summary = null)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 glib.option_context.OptionContext.setTranslateFunc and glib.option_context.OptionContext.setTranslationDomain).
Parameters
summary | a string to be shown in --help output before the list of options, or null |