mconv_ungetc -

       Copyright (C) 2001 Information-technology Promotion Agency (IPA)
       Copyright (C) 2001-2011 National Institute of Advanced Industrial Science and Technology (AIST)
       Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free
       Documentation License <http://www.gnu.org/licenses/fdl.html>.

Version 1.8.4                                    Mon Sep 25 2023                             mconv_ungetc(3m17n)

       Push a character back to a code converter. The mconv_ungetc() function pushes character c back to code
       converter converter. Any number of characters can be pushed back. The lastly pushed back character is
       firstly read by the subsequent mconv_getc() call. The characters pushed back are registered only in
       converter; they are not written to the input source. The internal status of converter is updated
       appropriately.

           MERROR_CODING, MERROR_CHAR

       mconv_ungetc -

           If the operation was successful, mconv_ungetc() returns c. Otherwise it returns EOF and assigns an
           error code to the external variable merror_code.

mconv_getc(), mconv_putc(), mconv_gets()

       int mconv_ungetc (MConverter * converter, int c)