\newlength
\newlength{\arg}
The \newlength
command defines the mandatory argument as a
length
command with a value of 0in
. The argument must
be a control sequence, as in \newlength{\foo}
. An error
occurs if \foo
is already defined.
See Lengths, for how to set the new length to a nonzero value, and for more information about lengths in general.