Associates a function with group which will be called from g_option_context_parse() when an error occurs. Note that the user data to be passed to error_func can be specified when constructing the group with g_option_group_new(). Since 2.6
a function to call when an error occurs
See Implementation
Associates a function with group which will be called from g_option_context_parse() when an error occurs. Note that the user data to be passed to error_func can be specified when constructing the group with g_option_group_new(). Since 2.6