Altera Nios II C2H Compiler Instrukcja Użytkownika Pobierz pdf (Strona 69)

Altera Corporation 9.1 3–29

November 2009 Nios II C2H Compiler User Guide

C-to-Hardware Mapping Reference

Consider the simple struct declaration shown in Example 3–22.

Example 3–22. Structure Declaration

struct s

{

int element_a;

int element_b;

int element_c;

} my_struct;

In this example, the expression (my_struct.c) translates to the

following:

*((int *)((void *)&my_struct + 2*sizeof(int)))

Structure Pointer Operator ->

The structure pointer operator is used to access a single member of a

structure or union via a pointer to the structure or union. The structure

pointer operator behaves similarly to the member operator, except that

the left-hand side of the operator must be a pointer.

The structure pointer operation on a struct(e.g. mystruct->a) is

equivalent to Example 3–23.

Example 3–23. Converted struct Pointer Operation

*((pointer_to_type_of_a) ((void *)mystruct + offset_of_a))

The structure pointer operation on a union (e.g. myunion->a) is

equivalent to Example 3–24.

Example 3–24. Converted union Pointer Operation

*((pointer_to_type_of_a)myunion)

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Altera Nios II C2H Compiler Instrukcja Użytkownika Strona 69