Effects: If
parray is a null pointer, allocates an array of
pointers to
void of unspecified size and stores a pointer to
its
first element in
parray. The function then extends the array
pointed at by
parray as necessary to include the element
parray[idx]. Each newly allocated element of the array is initialized to a null
pointer
. The reference returned is invalid after any other operation on the
object
. However, the value of the storage referred to is retained, so
that until the next call to
copyfmt,
calling
pword
with the same index yields another reference to the same value
. If the function fails
and
*this
is a base class subobject of a
basic_ios<>
object or subobject, the effect is equivalent to calling
basic_ios<>::setstate(badbit)
on the derived object (which may throw
failure)
.