mfontset_modify_entry -

       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                    mfontset_modify_entry(3m17n)

       Modify the contents of a fontset. The mfontset_modify_entry() function associates, in fontset fontset, a
       copy of font with the script / language pair or with charset.

       Each font in a fontset is associated with a particular script/language pair, with a particular charset,
       or with the symbol Mnil. The fonts that are associated with the same item make a group.

       If script is not Mnil, it must be a symbol identifying a script. In this case, language is either a
       symbol identifying a language or Mnil, and font is associated with the script / language pair.

       If charset is not Mnil, it must be a symbol representing a charset object. In this case, font is
       associated with that charset.

       If both script and charset are not Mnil, two copies of font are created. Then one is associated with the
       script / language pair and the other with that charset.

       If both script and charset are Mnil, font is associated with Mnil. This kind of fonts are called fallbackfonts.

       The argument how specifies the priority of font. If how is positive, font has the highest priority in the
       group of fonts that are associated with the same item. If how is negative, font has the lowest priority.
       If how is zero, font becomes the only available font for the associated item; all the other fonts are
       removed from the group.

       If layouter_name is not Mnil, it must be a symbol representing a mdbFLT (font layout table). In that
       case, if font is selected for drawing an M-text, that font layout table is used to generate a glyph code
       sequence from a character sequence.

           MERROR_SYMBOL

       mfontset_modify_entry -

           If the operation was successful, mfontset_modify_entry() returns 0. Otherwise it returns -1 and
           assigns an error code to the external variable merror_code.

       int mfontset_modify_entry (MFontset * fontset, MSymbol script, MSymbol language, MSymbol charset, MFont *
       spec, MSymbol layouter_name, int how)