On Tue, Feb 29, 2000 at 11:20:25AM -0600, Bill Wendling wrote:
> Also sprach Ben Kosse:
> } > Well the problem is bad 'C' code. It's not the compiler's fault. It's
> } > just doing what it's told to do.
> } >
> } > char str[12]="mystring";
> } >
> } > declares a string on the stack with room for 12 bytes. However it is
> } > initialized with only 9 (8 characters + the implied \0). So the rest
> } > of the area has to be zeroed, which the compiler does.
> } No it doesn't. For all C is required to care about, it could be stored as:
> } "mystring\0bla" The definition is 12 bytes on the stack, the first nine being
> } "mystring\0".
> }
> Depends on where the char str[12] is placed. If it is global, then it is
> zeroed cause it's static...If it's an auto, then it can (and probably
> does) have garbage after the terminating \0.
>
The problem is that "mystring" is a null-terminated ASCII string and char str[12]
is an array of 12 chars, not an ASCII string. One of the arguable aspects of C
is that _all_ elements get initialized in an array. It is similar to
{
int zeros[10]={ 0 };
struct {
int foo;
int bar;
}x = { 1 };
}
In both cases, the entire array or structure has to be cleared. As Richard
said above, "the problem is bad 'C' code." Personally, I think that
auto-initialization of auto variables is a nasty feature, and I try to
avoid using it in my own code in cases where it is inequivalent to
initialization of global variables.
dave...
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