Sometimes LaTeX will give the warning like
Missing character: There is no <xxx> in font <xxx>!
How to test it (I mean a macro like \IfCharExist)? And how to replace this missing character with something else like \rule?
Sometimes LaTeX will give the warning like
Missing character: There is no <xxx> in font <xxx>!
How to test it (I mean a macro like \IfCharExist)? And how to replace this missing character with something else like \rule?
\iffontcharprimitive that tests whether a given slot number (0-255) corresponds to an existing character in a given font. See pp. 13-14 of the e-TeX manual. – GuM Jan 10 '18 at 13:12