🚀 go-pugleaf

I cannot decide whether the following is a bug or a feature :)

Consider the following code:

#include"stdio.h"

struct Toilday {
   char   header[6]; 
   long   date;
   char   wname[16];
};

main()
{
  Toilday oilday;

  printf("oilday: %d\n\n", sizeof(oilday));
  printf("oilday.header: %d\n", sizeof(oilday.header));
  printf("oilday.date: %d\n", sizeof(oilday.date));
  printf("oilday.wname: %d\n", sizeof(oilday.wname));
}



It produces the following output:

oilday: 28

oilday.header: 6
oilday.date: 4
oilday.wname: 16

Now if my arithmetic is up to speed, I think the total size of the 
structure should be 26.  But is weighs in at 28.  I did some 
debugging and found the extra two bytes between the header and date fields.  
Adding more fields of different types adds more unaccounted for 
bytes.  In the original data structure I need for the program I'm 
writing, I found 17 extra bytes.  I couldn't find a pattern to the 
addition of bytes, but they seem to occur mostly between 
fields of different types.

The reason I discovered this is that I am writing code that needs to 
be able to write data into oilday as a void pointer.  In Borland's 
Turbo C++, the structures had no extra bytes so I could calculate the 
field positions in the variable as offsets from the base address of 
oilday.  But with the extra bytes in the structure, the calculation 
does not hold true.

I am using Linux 1.2.1, slackware release 2.2.0.  My version of the 
GCC compiler is 2.6.3.  I used the command g++ to compile the code, 
and used the filename test.C.  I used no command line options for the 
compile.  GCC was automatically installed by the slackware setup 
program.

Incidently, the GCC manual where I got this address indicates that 
BUG-GCC and HELP-GCC are mailing lists.  Am I allowed to join these 
lists?  If so, what is the administrative address?  They weren't 
listed in the GCC manual.


Thank you,
-----------------------------------------------
Travis Bauer
http://acc.jc.edu/~bauer
We don't understand the software,
and we don't always understand the hardware,
but we can see the blinking lights!
-----------------------------------------------