🚀 go-pugleaf

"joe (j.) halpin" <jhalpin@bnr.ca> wrote:

>In 3.7.3.2.4 the January working paper says:
>
>4 A deallocation function can free the storage referenced by the pointer
>  given  as  its  argument and renders the pointer invalid.  The storage
>  can be made available for further allocation.  An invalid pointer con-
>  tains an unusable value:  it cannot even be used in an expression.

I interpret this as meaning the _value_ of the pointer cannot be used in
an expression.

>
>This sounds as though, in the following:
>
>char *pc = new char[128];
>delete pc;
    ^^^^
delete[] pc;

>pc = 0;
>
>it makes the final assignment (an expression) invalid.

The value of the pointer is not used in the expression, so it's OK.

>In fact, it sounds like it also rules out things like 'if(pc == 0)
>...' after the above fragment.

After the final assignment, the pointer's value is no longer invalid, so
it can be used (though obviously not dereferenced while NULL).

By my interpretation, (pc == 0) would, however, be invalid after the
delete but before the assignment of 0.

Cheers,

John
-----------------------------------------------------------------
John Bain                  
johnb@pivotal-dm.ccmail.compuserve.com 
-----------------------------------------------------------------



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