Cray Character Pointers

If a pointee is declared as a character type, its Cray pointer is a Cray character pointer.

Purpose of Cray Character Pointers

A Cray character pointer is a special data type that allows f90 to maintain character strings by keeping track of the following:

• Byte address of the first character of the string

• Length

• Offset

An assignment to a Cray character pointer alters all three. That is, when you change what it points to, all three change.

Declaration of Cray Character Pointers

For a pointee that has been declared with an assumed length character type, the Cray pointer declaration statement declares the pointer to be a Cray character pointer.

1. Before the Cray pointer declaration statement, declare the pointee as a character type with an assumed length.

2. Declare a Cray pointer to that pointee.

3. Assign a value to the Cray character pointer.

You can use functions CLOC or FCD, both nonstandard intrinsics.

Example: Declare Ccp to be a Cray character pointer and use CLOC to make it point to character string s.

	CHARACTER*(*) a
	POINTER ( Ccp, a )
	CHARACTER*80  :: s = "abcdefgskooterwxyz"
	Ccp = CLOC( s )

Operations on Cray Character Pointers

You can do the following operations with Cray character pointers:

where Ccp1 and Ccp2 are Cray character pointers and i is an integer.

Restrictions on Cray Character Pointers and Pointees

All restrictions to Cray pointers also apply to Cray character pointers. In addition, the following apply:

• A Cray character pointee cannot be an array.

• In a relational operation, a Cray character pointer can be mixed with only another Cray character pointer--not with a Cray pointer, not with an integer.

• A relational operation applies only to the character address and the bit offset; the length field is not involved.

• Cray character pointers must not appear in EQUIVALENCE statements, or any storage association statements. (The size can vary with the platform.)

• Cray character pointers are not optimized.

• Code containing Cray character pointers is not parallelized.

• A Cray character pointer in a list of an I/O statement is treated as an integer.