\newwrite\mztpOUT
\newbox\mztpBOX
\immediate\openout\mztpOUT=\jobname.mztp

\newcommand{\mztpMeasure}[2]{%
\setbox\mztpBOX\hbox{#1}%
\immediate\write\mztpOUT{#2 \the\wd\mztpBOX\space\the\ht\mztpBOX\space\the\dp\mztpBOX}%
\usebox\mztpBOX}