message: extract the right hex string
diff: @@ -97,7 +97,8 @@ if (ADIOS2_HAVE_MPI)
  string(LENGTH ${MPIFILEDATA} DATALENGTH)
  math(EXPR last_hex_index "(${DATALENGTH} / 2) - 1")
  foreach(hex_index RANGE ${last_hex_index})
  - string(SUBSTRING "${MPIFILEDATA}" "${hex_index}" "2" char)
  + math (EXPR str_loc "2*${hex_index}")
  + string(SUBSTRING "${MPIFILEDATA}" "${str_loc}" "2" char)
  #math (EXPR dec_char "0x${char}" )
  from_hex(${char} dec_char)
  if ((${dec_char} LESS 9) OR (${dec_char} GREATER 126) OR ((${dec_char} GREATER 13) AND (${dec_char} LESS 32)))
  