tcolorbox: newtcbtheorem referencing

Question

Using newtcbtheorem, how do we reference the created environment?

documentclass{article}
usepackage[most]{tcolorbox}
tcbuselibrary{theorems}
usepackage{cleveref}
crefname{exa}{example}{Example}
Crefname{exa}{Example}{Example}
newtcbtheorem[auto counter, number within = section]
{Example}{Examsmash{p}le}{%                                                        
  breakable,
  fonttitle = bfseries,
  colframe = blue!75!black,
  colback = blue!10
}{exa}
begin{document}
begin{Example}{Example}{exam}
  Some example
end{Example}
noindent
Cref{exa:exam}
end{document}

Using tcbmaketheorem, I used newcounter{exa}, but I can't get referencing to work here.

Gonzalo Medina · Accepted Answer

You need to define the format for the new object; in this case, for tcb@cnt@Example, using something like

crefformat{tcb@cnt@Example}{example~#2#1#3}
Crefformat{tcb@cnt@Example}{Example~#2#1#3}

or any other format you want. A complete example:

documentclass{article}
usepackage[most]{tcolorbox}
usepackage{cleveref}

makeatletter
crefformat{tcb@cnt@Example}{example~#2#1#3}
Crefformat{tcb@cnt@Example}{Example~#2#1#3}
makeatother
newtcbtheorem[auto counter, number within = section]
{Example}{Examsmash{p}le}{%                                                        
  breakable,
  fonttitle = bfseries,
  colframe = blue!75!black,
  colback = blue!10
}{exa}
begin{document}
begin{Example}{Example}{exam}
  Some example
end{Example}
noindent
Cref{exa:exam} and~cref{exa:exam}

end{document}

The correct name to be used in Crefformat, and crefformat can be obtained from one of the warnings obtained in the original code using Cref without the proper definitions:

LaTeX Warning: Cref reference format for label type `tcb@cnt@Example' undefined on input line 21.

Thomas F. Sturm · Answer

Since tcolorbox version 2.41 (2013/07/23), there is integrated support for the cleveref package. You just have to move crefname and Crefname as options into newtcbtheorem:

documentclass{article}
usepackage[most]{tcolorbox}
tcbuselibrary{theorems}
usepackage{cleveref}
newtcbtheorem[auto counter, number within = section,
  crefname={example}{Example},
  Crefname={Example}{Example} ]
{Example}{Examsmash{p}le}{%
  breakable,
  fonttitle = bfseries,
  colframe = blue!75!black,
  colback = blue!10
}{exa}
begin{document}
begin{Example}{Example}{exam}
  Some example
end{Example}
noindent
Cref{exa:exam} and~cref{exa:exam}.
end{document}

The output is identical to that of the solution of Gonzalo Medina.

Mathias Pilch · Answer

As of 2020-09-08, the previous offered solutions do not work anymore. The cleveref 4.31 (2020-07-31) documentation provides an example and solution to this problem on page 372: the label type optional argument is used to feed cleveref with the needed name information.
MWE:
documentclass{article}
usepackage{tcolorbox}
tcbuselibrary{theorems}
usepackage{cleveref}

newtcbtheorem{example}{Example}{label type=example}{exa}

begin{document}

begin{example}{title}{label}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
end{example}
Checking if textbf{cleveref} works: cref{exa:label} and Cref{exa:label}.

end{document}

tcolorbox: newtcbtheorem referencing

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