Intrinsic Data Types

Intel® Fortran provides the following intrinsic data types:

• INTEGER

  The following kind parameters are available for data of type integer:

  • INTEGER([KIND=]1) or INTEGER*1

  • INTEGER([KIND=]2) or INTEGER*2

  • INTEGER([KIND=]4) or INTEGER*4

  • INTEGER([KIND=]8) or INTEGER*8

• REAL

  The following kind parameters are available for data of type real:

  • REAL([KIND=]4) or REAL*4

  • REAL([KIND=]8) or REAL*8

  • REAL([KIND=]16) or REAL*16

• DOUBLE PRECISION

  No kind parameter is permitted for data declared with type DOUBLE PRECISION. This data type is the same as REAL([KIND=]8).

• COMPLEX

  The following kind parameters are available for data of type complex:

  • COMPLEX([KIND=]4) or COMPLEX*8

  • COMPLEX([KIND=]8) or COMPLEX*16

  • COMPLEX([KIND=]16) or COMPLEX*32

• DOUBLE COMPLEX

  No kind parameter is permitted for data declared with type DOUBLE COMPLEX. This data type is the same as COMPLEX([KIND=]8).

• LOGICAL

  The following kind parameters are available for data of type logical:

  • LOGICAL([KIND=]1) or LOGICAL*1

  • LOGICAL([KIND=]2) or LOGICAL*2

  • LOGICAL([KIND=]4) or LOGICAL*4

  • LOGICAL([KIND=]8) or LOGICAL*8

• CHARACTER

  There is one kind parameter available for data of type character: CHARACTER([KIND=]1).

• BYTE

  This is a 1-byte value; the data type is equivalent to INTEGER([KIND=]1).

The intrinsic function KIND can be used to determine the kind type parameter of a representation method.

For more portable programs, you should not use the forms INTEGER([KIND=]n) or REAL([KIND=]n). You should instead define a PARAMETER constant using the SELECTED_INT_KIND or SELECTED_REAL_KIND function, whichever is appropriate. For example, the following statements define a PARAMETER constant for an INTEGER kind that has 9 digits:

  INTEGER, PARAMETER :: MY_INT_KIND = SELECTED_INT_KIND(9)
    ...
  INTEGER(MY_INT_KIND) :: J
    ...

Note that the syntax :: is used in type declaration statements.

The following sections describe the intrinsic data types and forms for literal constants for each type.