pTAL Reference Manual (G06.24+, H06.09+, J06.03+)

10 Pointers
This section describes the syntax for declaring and initializing pointers you manage yourself. You
can declare the following kinds of pointers:
• Simple pointer—a variable into which you store a memory address, usually of a simple variable
or array, which you can access with this simple pointer.
• Structure pointer—a variable into which you store the memory address of a structure which
you can access with this structure pointer.
The compiler allocates 32 bits for all pointers except .SG. In expressions involving addresses,
however, the compiler treats all operands as if they were word addresses except extended addresses
the and addresses of strings. The pointer’s object data type determines the pointer’s address type
and identifies the addressing type and location of data that your pointers will reference. For
information about working with addresses, see Chapter 5 (page 69).
Some portions of this section describe how you reference data in system globals. System globals
can be accessed only by programs running as privileged procedures.
Topics:
• Overview of Pointer Declaration (page 161)
• Declaring VOLATILE Pointers (page 163)
• Address Types (page 164)
• Declaring Simple Pointers (page 170)
• Initializing Simple Pointers (page 172)
• REAL and REAL(64) Numeric (page 62)
• Initializing Structure Pointers (page 174)
• Declaring System Global Pointers (page 176)
Overview of Pointer Declaration
This subsection gives you the general pointer syntax and explains the syntax elements.
Overview of Pointer Declaration 161