--- !ruby/object:RI::MethodDescription 
aliases: []

block_params: 
comment: 
- !ruby/struct:SM::Flow::P 
  body: Return the appropriate error message in POSIX-defined format. If no error has occurred, returns nil.
full_name: GetoptLong#error_message
is_singleton: false
name: error_message
params: ()
visibility: public