REAL

The REAL statement specifies the type of a symbolic constant, variable, array, function, or dummy function to be real, and optionally specifies array dimensions and size, and initializes with values.

REAL [*len[,]] v[*len[/c/]] [, v[*len[/c/]] ...

Parameter	Description
v	Name of a variable, symbolic constant, array, array declarator, function, or dummy function
len	Either 4, 8, or 16 (SPARC only), the length in bytes of the symbolic constant, variable, array element, or function
c	List of constants for the immediately preceding name

Description

Following are descriptions for REAL, REAL*4, REAL*8, and REAL*16.

REAL

For a declaration such as REAL W, the variable W is usually a REAL*4 element in memory, interpreted as a real number. Specifying the size is nonstandard. @

The default size, for a declaration such as REAL H, can be altered by compiling with any of the options -dbl, -r8, or -xtypemap. See the discussion in Chapter 2 for details.

REAL*4 @

For a declaration such as REAL*4 W, the variable W is always a REAL*4 element in memory, interpreted as a single-width real number.

REAL*8 @

For a declaration such as REAL*8 W, the variable W is always a REAL*8 element in memory, interpreted as a double-width real number.

REAL*16 @

(SPARC only) For a declaration such as REAL*16 W, the variable W is always an element of type REAL*16 in memory, interpreted as a quadruple-width real.

Examples

Example 1: Simple real variables--these declarations are all equivalent:

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       REAL U, V(9)
       REAL*4 U, V(9)
       REAL U*4, V(9)*4

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Example 2: Initialize variables (REAL*16 is SPARC only):

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       REAL U/ 1.0 /, V/ 4.3 /, D*8/ 1.0 /, Q*16/ 4.5 / 

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Example 3: Specify dimensions for some real arrays:

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       REAL A(10,100), V(10)
       REAL X*4(10), Y(10)*4

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Example 4: Initialize some arrays:

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       REAL A(10,100) / 1000 * 0.0 /, B(2,2) /1.0, 2.0, 3.0, 4.0/ 

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Example 5: Double and quadruple precision (REAL*16 is SPARC only):

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       REAL*8  R
       REAL*16 Q
       DOUBLE PRECISION D

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In the above example, D and R are both double precision; Q is quadruple precision.