Sets the parameter string to be used by the commandline handling of @application.
This function registers the argument to be passed to g_option_context_new() when the internal #GOptionContext of @application is created.
See g_option_context_new() for more information about @parameter_string.
a string which is displayed in the first line of --help output, after the usage summary programname [OPTION...].
2.56
See Implementation
Sets the parameter string to be used by the commandline handling of @application.
This function registers the argument to be passed to g_option_context_new() when the internal #GOptionContext of @application is created.
See g_option_context_new() for more information about @parameter_string.