Re: Struct assignment

Flash Gordon <spam@xxxxxxxxxxxxxxxxxx> writes:
Grey Alien wrote, On 30/06/07 17:43:
If I have the ff struct:
struct A
{
unsigned int i;
char s[LONG_ENOUGH];
} a, b;
And use them in code like this:
a.i = 42 ;
strcpy(a.s,"test");
b.i = 100 ;
b = a ;
at this point, a (bitwise?) copy of a is made to b.

It is not a bitwise copy, it is a copy of all the elements in the struct.

Yes -- and that can be, and commonly is, implemented as a bitwise copy
of the struct.

Suppose there's a gap between the members "i" and "s". After the
assignment "b = a;", the gaps in "a" and "b" may or may not have the
same contents. The assignment can be done either as a bitwise copy or
by copying the members one-by-one, leaving any gaps alone.

99% of the type, this doesn't matter because you're never going to
look at what's in the gaps anyway.

--
Keith Thompson (The_Other_Keith) kst-u@xxxxxxx <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
.

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