def store_externcount(count)   #:nodoc:
    record   = 0x0016          # Record identifier
    length   = 0x0002          # Number of bytes to follow

    cxals    = count           # Number of external references

    header = [record, length].pack('vv')
    data   = [cxals].pack('v')

    prepend(header, data)
  end
def store_externcount(count)   #:nodoc:
    record   = 0x0016          # Record identifier
    length   = 0x0002          # Number of bytes to follow

    cxals    = count           # Number of external references

    header = [record, length].pack('vv')
    data   = [cxals].pack('v')

    prepend(header, data)
  end
Write BIFF record EXTERNCOUNT to indicate the number of external sheet
 references in a worksheet.

 Excel only stores references to external sheets that are used in formulas.
 For simplicity we store references to all the sheets in the workbook
 regardless of whether they are used or not. This reduces the overall
 complexity and eliminates the need for a two way dialogue between the formula
 parser the worksheet objects.