Drawing an angle via \pic doesn't work

I want to draw an angle between two points, but for some reason TexStudio can't find tikz's \pic function (though I imported the 'angles' library).

Here is my code:

\documentclass[12pt, a4paper]{standalone}

\usepackage{tikz}

\usetikzlibrary{angles}

\begin{document}
\begin{tikzpicture}
\pic [draw, angle eccentricity=1.5] {angle = (0,1) -- (0,0) -- (1,0)};
\end{tikzpicture}
\end{document}


Could someone please tell me where my mistake is?

Thanks!

You need to use named coordinates I think:

\documentclass[12pt, a4paper]{standalone}

\usepackage{tikz}

\usetikzlibrary{angles}

\begin{document}
\begin{tikzpicture}
\coordinate (O) at (0,0);
\coordinate (A) at (0,1);
\coordinate (B) at (1,0);

\pic [draw, angle eccentricity=1.5] {angle=A--O--B};
\end{tikzpicture}
\end{document}

• Indeed - in the TikZ/PGF manual, in the section about the Angles library, it says "The three points (A), (B), and (C) must be the names of nodes or coordinates; you cannot use direct coordinates like (1,1) here." – Jānis Lazovskis Feb 27 '17 at 15:56