The package ltxnew provides the \new, \renew and \provide prefixes for checking definitions. It is designed to work with e-TeX distributions of LaTeX and relies on the LaTeX macro \@ifdefinable. Local allocation of counters, dimensions, skips, muskips, boxes, tokens and marks are provided by the etex package. \new and \renew as well as \provide may be used for all kind of control sequences. Please refer to the section “Using \new” of the PDF documentation.