Using ligatures as Unicode

Question

I use TeX Live. See my example:

\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[english]{babel}
\begin{document}
Check ligatures: first % here I have ligature for "fi"
\end{document}

I have Unicode symbol here: fi. When I compile the above LaTeX file I get:

! Package ucs Error: Unknown Unicode character 64257 = U+FB01

Then I apply the LaTeX system recommendation and compile the following file:

\documentclass{article}
\usepackage[utf8x]{inputenc}
\usepackage[english]{babel}
\DeclareUnicodeCharacter{FB01}{fi}% Here I defined a Unicode ligature
\begin{document}
Check ligatures: first
\end{document}

But when I compile this LaTeX file I get:

! Missing number, treated as zero.
<to be read again>
                   F
l.4 \DeclareUnicodeCharacter{FB01}{fi}

So my question is: How can I input ligatures in a LaTeX file using just the ligature's Unicode symbol?

Answer 1

There are two problems with the code:

1. Use [utf8] instead of [utf8x]
2. The second parameter of \DeclareUnicodeCharacter is what the character will be replaced with, so it's meaningless to put the character there again. Replace it with what you reallly need (f and i will be joined in a ligature by TeX, as usual): \DeclareUnicodeCharacter{FB01}{fi}

After these changes the code will work as desired.