🚀 go-pugleaf

In article <4cth4e$4q@odin.funcom.no>,
Eivind Eklund <eivind@odin.funcom.com> wrote:
>Are zero in an integer required to be represented by binary zeros?
>I know it is not required for floats and pointers, so memset()ing a 
>structure to 8-bit zeros are not correct if it contain pointers or 
>floating point values, but what about integers? Ie, if I have
>
>struct intstruct {
>  int a;
>  long b;
>  short c;
>};
>..
>struct intstruct teststruct;
>memset(&teststruct, 0, sizeof(teststruct));
>
>Is teststruct.a, teststruct.b, and teststruct.c guaranteed to be == 0?

Eivind,

there is an (elegant, IMHO) way to initialize structures
as if you had written <member> = 0 for any member.
The standard requires this for objects of static storage type.
It also has the advantage to work for pointers and floating point
as well as numbers. It also applies recursively to structs and
unions within a struct or union. Just make one
structure static and assign it to whatever other (maybe
automatic) struct you have. E.g.

static struct intstruct {
  int a;
  long b;
  short c;
  double d;
  char *e;
} zero;

...

void
foo (void)
{
	struct intstruct { ... } bar;
	...
	bar = zero; /* Much more readable than memset(&bar, 0, sizeof bar); */
}

Good compilers will certainly use a memcpy equivalent
to code the strcuture assignment.

Bye, Jens
-- 
SIGSIG -- signature too long (core dumped)