Warning

The Warning module contains a single method named warn, and the module extends itself, making Warning.warn available. Warning.warn is called for all warnings issued by Ruby. By default, warnings are printed to $stderr.

By overriding Warning.warn, you can change how warnings are handled by Ruby, either filtering some warnings, and/or outputting warnings somewhere other than $stderr. When Warning.warn is overridden, super can be called to get the default behavior of printing the warning to $stderr.

Instance Methods

warn(msg) → nil

2.5 View on GitHub

          
            static VALUE
rb_warning_s_warn(VALUE mod, VALUE str)
{
    Check_Type(str, T_STRING);
    rb_must_asciicompat(str);
    rb_write_error_str(str);
    return Qnil;
}

Writes warning message msg to $stderr, followed by a newline if the message does not end in a newline. This method is called by Ruby for all emitted warnings.