next up previous contents index
Next: Constants Up: Data Types Previous: Guidelines

Non-standard Data Types

  Although Standard Fortran only provides the above six data types, many systems provide additional ones. You may come across data type names such as: LOGICAL*1, INTEGER*2, REAL*8, COMPLEX*16, etc. The number after the asterisk indicates the number of bytes of storage used for each datum (a byte being a group of 8 bits). This notation has a certain logic but is totally non-standard. The use of a term like REAL*8 when it is simply a synonym for DOUBLE PRECISION seems particularly pointless. There are, of course, circumstances when types such as COMPLEX*16 are necessary but the price to be paid is the loss of portability.

Helen Rowlands