Path: utzoo!utgpu!news-server.csri.toronto.edu!qucis!kelley
From: kelley@qucis.queensu.CA (Todd Kelley)
Newsgroups: comp.unix.questions
Subject: dbx treats &(array[0]) differently from array when length is odd
Keywords: dbx odd array length
Message-ID: <805@qusunc.queensu.CA>
Date: 18 Jul 90 22:57:22 GMT
Organization: Queen's University, Kingston, Ontario, Canada
Lines: 38


Hello unix experts.  I'm puzzled by dbx -- it gives different results for
the command  "print array"  than it gives for "print &(array[0])" on
a SUN4.  If the size of the array is odd, the first character of the string
is ommitted.  The problem goes away if the length of the array is even.  Is
this an alignment problem?

Here is the offending C program, and an excerpt from a dbx session:
______________________________________________
#include <stdio.h>
typedef struct {
            char my_string[9];
        }elem_type;
main()
{
    elem_type my_element;

    strcpy(my_element.my_string,"abc");
    printf(my_element.my_string);
    printf("\n");
}
______________________________________________

stopped in main at line 10 in file "test.c"
   10       printf(my_element.my_string);
(dbx) print my_element.my_string
my_element.my_string = "bc"
(dbx) print &(my_element.my_string[0])
&my_element.my_string[0] = 0xf7fffd34 "abc"
(dbx) cont
abc

execution completed, exit code is 0
program exited with 0
(dbx) quit

If you can explain this behaviour, please send email to me.
Todd Kelley (kelley@qucis.queensu.ca)