\enabletrackers[buffers.visualize]

\starttext

\definetyping[C] % [option=C]
\setuptyping[C][escape=yes]

\startC
#include <stdio.h>
int main(){
   return 0;
   /BTEX{\em unreachedCode;}/ETEX
}
\stopC

\setuptyping[escape=yes]

\startTEX
/BTEX\em sometex/ETEX
/BTEX\em sometex/ETEX \after
\before /BTEX\em sometex/ETEX
\before /BTEX\em sometex/ETEX \after
\before /BTEX\em sometex/ETEX \inbetween /BTEX\em sometex/ETEX \after
\before \after
\stopTEX

\setuptyping[TEX][escape=no]

\startTEX
/BTEX\em sometex/ETEX
/BTEX\em sometex/ETEX \after
\before /BTEX\em sometex/ETEX
\before /BTEX\em sometex/ETEX \after
\before /BTEX\em sometex/ETEX \inbetween /BTEX\em sometex/ETEX \after
\before \after
\stopTEX

\stoptext
