# Why \pdfstrcmp shows unrecongnized command in texstudio? [duplicate]

I have used this \pdfstrcmp as in the following to set the different

\makeatletter
\newcommand{\setappendix}{Appendix~\thechapter}
\newcommand{\setchapter}{Chapter~\thechapter~}
\titleformat{\chapter}[display]{\sffamily\huge\bfseries \color{sec}}{}{0.5ex} %
{\ifnum\pdfstrcmp{\@currenvir}{appendices}=0
\setappendix
\else
\setchapter
\fi
\filleft \\%
\titlerule[1pt]
\vspace{1ex}%
#1\filleft\\
\vspace{1ex}%
\titlerule[3pt]}
\makeatother


But I dont know for what reason, though it gives the desire output, it gives me the following popup in texstudio unrecongnized command.

## Shall I ignore the popup?

If I dont, will it create any issues?

I am running pdflatex with Miktex 2.9 in Windows 10 machine (and using biber as backend with biblatex).

## MWE:

\documentclass[oneside]{book}

\usepackage[explicit]{titlesec}
\usepackage[titletoc]{appendix}

\makeatletter
\newcommand{\setappendix}{Appendix~\thechapter}
\newcommand{\setchapter}{Chapter~\thechapter~}
\titleformat{\chapter}[display]{\sffamily\huge\bfseries}{}{0.5ex} %
{\ifnum\pdfstrcmp{\@currenvir}{appendices}=0
\setappendix
\else
\setchapter
\fi
\filleft \\%
\titlerule[1pt]
\vspace{1ex}%
#1\filleft\\
\vspace{1ex}%
\titlerule[3pt]}

\makeatother

\begin{document}

\chapter{This is usual Chapter}

\begin{appendices}
\chapter{This is appendix}
\end{appendices}

\end{document}


## marked as duplicate by TeXnician, Bobyandbob, Troy, moewe, Stefan PinnowMay 10 '18 at 11:05

• You have to worry about something if and only if it comes up in the .log file (as error or slightly less serious as warning). This is just your editor telling you it doesn't know a command. You only need to worry if TeX tells you it doesn't know the command in the .log file after an attempt to compile your document. – moewe May 10 '18 at 8:48