If you have a struct (or in C++ a class), you use these operators to access
the members of that struct (or object). If the object is a pointer to an
object then you need to use the arrow (->) indirection. If the object is the
actual object (if you see what I mean) then you need to use the dot.

typedef struct error_code_struct
{
    int  bytes_provided;
    int  bytes_avail;
    char expt_id[7];
    char RESERVED;
    char expt_data[100];
} Error_Code_Struct;

Error_Code_Struct  err_code;
Error_Code_Struct  *perr_code;

main() {
  ...

  printf("Bytes Provided = %i\n", err_code.bytes_provided);

  perr_code = &err_code;      /* Get the reference (pointer) to err_code */

  printf("Bytes Provided = %i\n", perr_code->bytes_provided);

  ...
}


In C++:

Class FooBar {
...
Public:
        int Value;
...
};


Foobar aFoo;
Foobar *aBar;

main () {
        ...

        printf("Value = %i\n", aFoo.Value);

        aBar = new Foobar();

        printf("Value = %i\n", aBar->Value);

        ...
}




-----Original Message-----
From: Gene_Gaunt@ReviewWorks.com [mailto:Gene_Gaunt@ReviewWorks.com]
Sent: 26 July 2002 13:28
To: C400-l@midrange.com
Subject: [C400-L] dot-indirection and arrow-indirection operators?

What are dot-indirection and arrow-indirection operators?   They appear in
WDS C/C++ Language Reference chapter 5's operator precedence and
associativity table under rank level "4":

object .* ptr_to_member

object ->* ptr_to_member

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