After building this code:

% !TeX program = xelatex
\documentclass{report}        % or some other class
some text

I get the following warning in the log file:

("C:\Program Files\MiKTeX 2.9\tex\latex\base\ifthen.sty"
Package: ifthen 2014/09/29 v1.1c Standard LaTeX ifthen package (DPC)
Invalid UTF-8 byte or sequence at line 1311 replaced by U+FFFD.
Invalid UTF-8 byte or sequence at line 1313 replaced by U+FFFD.
Invalid UTF-8 byte or sequence at line 1315 replaced by U+FFFD.

First, the ifthen.sty file I have is only 152 lines long. Second thing is, that I didn't include it in my document. has anyone experienced anything similar?

I use Win7 64bit, TexStudio 2.12.2.

  • 2
    The ifthen package gets included by algorithm2e. If you have a look at the source code of the algorithm2e package, you can see that the lines raising the warnings contain an ç and ü.
    – epR8GaYuh
    Commented Jun 1, 2017 at 14:28
  • 2
    How to read the log file: if the opening ( has already been closed by a matching ), then the message is not from opening that file. Look back to the ( that opens the block with those warning messages. Commented Jun 1, 2017 at 14:32
  • Silly me. Indeed, after changing the encoding, it works fine. Thanks, guys. Commented Jun 1, 2017 at 14:41

1 Answer 1


They're just annoying warnings; the package should have

1307 \DeclareOption{turkish}{%
1308 \renewcommand{\listalgorithmcfname}{Algoritma Listesi}%
1309 \renewcommand{\algorithmcfname}{Algoritma}%
1310 \renewcommand{\algorithmautorefname}{algoritma}%
1311 \renewcommand{\algorithmcflinename}{\c{c}izgi}%
1312 \renewcommand{\algocf@typo}{}%
1313 \renewcommand{\@algocf@procname}{Prosed\"ur}%
1314 \renewcommand{\@algocf@funcname}{Fonksiyon}%
1315 \renewcommand{\procedureautorefname}{prosed\"ur}%
1316 \renewcommand{\functionautorefname}{fonksiyon}%
1317 \renewcommand{\algocf@languagechoosen}{turkish}%
1318 }%

instead of using Latin-1 characters for ç and ü. Turkish users will have surprises if they don't change manually those fixed words when using UTF-8 input.

LuaLaTeX users are in a worse situation, because the characters will issue errors and not warnings:

! String contains an invalid utf-8 sequence.
l.1311 \renewcommand{\algorithmcflinename}{

Unfortunately, there's no workaround for avoiding this while reading the package, so the warnings/errors cannot be skipped.

There is another error in algorithm2e (a spurious { at line 1061) that can cause memory overflow, besides issuing a warning at the end of the job. Making the bugs known to the package author seems useless.

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