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().
a function to call when an error occurs
2.6
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().