doc: miscellaneous documentation improvements * aspell-octave.en.pws: Add new words to spelling dictionary. * expr.txi: Use hyphens in "element-by-element" construction. * install.txi: Miscellaneous docstring improvements. * mk_undocumented_list: Update script. * xlim.m: Add ylim and zlim to function index. * data.cc: Add inf and nan to to function index. * file-io.cc: Add octave_tmp_file_name to function index. Expand docstring for SEEK_CUR and SEEK_END. * help.cc: Miscellaneous docstring improvements. * syscalls.cc: Improve docstrings for F_XXXX series of functions.

#include "mex.h"

void
mexFunction (int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
  mxArray *v = mxCreateDoubleMatrix (1, 1, mxREAL);

  double *data = mxGetPr (v);

  *data = 1.23456789;

  plhs[0] = v;
}