On Monday, 17 July, 2017 08:00, Richard Hipp <d...@sqlite.org> wrote:
> On 7/17/17, Keith Medcalf <kmedc...@dessus.com> wrote:
> > Also, a question. sqlite3_bind_pointer(C, P, T) and
> > sqlite3_value_pointer(C, P, T) indicates that T should be a "static
> > string".
> > Does this mean of type SQLITE_STATIC and that it cannot be a string
> > located on the stack (ie, an SQLITE_TRANSIENT), or is a copy made of
> > the string value (ala SQLITE_TRANSIENT) for future use?
> No copy is made of the string. SQLite merely keeps a pointer. If the
> memory that holds the string is deallocated or reused for some other
> purpose, bad things will happen.
Ok, understand. I presume therefore that this is NOT a database type but is
for passing around value types and contexts only. Therefore using a
quoted-string will point to something in the global string table built by the
compiler and therefore be static. Makes sense.
So if the sqlite3_bind_pointer is used to bind into a database column, that
value will be null when stored in the database? I suppose I could just try
this, but I thought I would ask you just to be sure ...
Example:
prepare("insert into table (col1, col2) values (?,?)")
bind_int64(...,1,intval)
bind_pointer(...,2,&intval, "carray")
step()
that col1 gets the integer and col2 gets a NULL? and that the bind_pointer
actual pointer value and type string is only accessible when the bound column
is accessed by something that uses the used the sqlite3_value type interfaces
(that does not actually originate or terminate as a database row -- and the
pointer type is not preserved in the database itself but would be persisted as
if NULL?)
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