Re: [sqlite] sqlite3_open_v2 vs. *ppDb=NULL

[Krystian Bigaj]

Thanks! I'm not sure how I've missed it.

-- 
Best regards,
Krystian Bigaj
On Oct 12, 2011 11:01 PM, "David Garfield" 
wrote:

> The documentation also says (http://sqlite.org/c3ref/open.html):
>
>   If the 3rd parameter to sqlite3_open_v2() is not one of the
>   combinations shown above optionally combined with other
>   SQLITE_OPEN_* bits then the behavior is undefined.
>
> Seems like the undefined behavior was non-dangerous.
>
> That sqlite3_errmsg() had to guess and guessed wrong is not
> surprising.
>
> --David Garfield
>
> Krystian Bigaj writes:
> > Hi,
> >
> > Documentation says that:
> >
> > "The only exception is that if SQLite is unable to allocate memory to
> hold
> > the sqlite3 object, a NULL will be written into *ppDb instead of a
> pointer
> > to the sqlite3 object"
> >
> > but I see it's not entirely true. This example below stores NULL in *ppDb
> > even when (I think) no memory allocation problems occurs:
> >
> > void TestOpenMisuse(void)
> > {
> >   sqlite3 *ppDb;
> >   int err = sqlite3_open_v2("whatever", , SQLITE_OPEN_CREATE , 0);
> >   if (ppDb == NULL)
> >   {
> > printf("ppDb==NULL, but err==%d, sqlite3_errmsg(ppDb)==%s",
> > err, sqlite3_errmsg(ppDb));
> >   }
> > }
> >
> >
> > Error code in this case will be err==21 (SQLITE_MISUSE) because
> > flag SQLITE_OPEN_CREATE cannot be there without SQLITE_OPEN_READWRITE -
> > which is docummented.
> > But sqlite3_errmsg(ppDb) will return "out of memory" (because
> ppDb==NULL),
> > which can be sometimes little misleading (for me as a SQLite newbie it
> was
> > ;).
> >
> > SQLite 3.7.8 (amalgamation)
> >
> > --
> > Best regards,
> > Krystian Bigaj
> > ___
> > sqlite-users mailing list
> > sqlite-users@sqlite.org
> > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] sqlite3_open_v2 vs. *ppDb=NULL

[David Garfield]

The documentation also says (http://sqlite.org/c3ref/open.html):

   If the 3rd parameter to sqlite3_open_v2() is not one of the
   combinations shown above optionally combined with other
   SQLITE_OPEN_* bits then the behavior is undefined.

Seems like the undefined behavior was non-dangerous.

That sqlite3_errmsg() had to guess and guessed wrong is not
surprising.

--David Garfield

Krystian Bigaj writes:
> Hi,
> 
> Documentation says that:
> 
> "The only exception is that if SQLite is unable to allocate memory to hold
> the sqlite3 object, a NULL will be written into *ppDb instead of a pointer
> to the sqlite3 object"
> 
> but I see it's not entirely true. This example below stores NULL in *ppDb
> even when (I think) no memory allocation problems occurs:
> 
> void TestOpenMisuse(void)
> {
>   sqlite3 *ppDb;
>   int err = sqlite3_open_v2("whatever", , SQLITE_OPEN_CREATE , 0);
>   if (ppDb == NULL)
>   {
> printf("ppDb==NULL, but err==%d, sqlite3_errmsg(ppDb)==%s",
> err, sqlite3_errmsg(ppDb));
>   }
> }
> 
> 
> Error code in this case will be err==21 (SQLITE_MISUSE) because
> flag SQLITE_OPEN_CREATE cannot be there without SQLITE_OPEN_READWRITE -
> which is docummented.
> But sqlite3_errmsg(ppDb) will return "out of memory" (because ppDb==NULL),
> which can be sometimes little misleading (for me as a SQLite newbie it was
> ;).
> 
> SQLite 3.7.8 (amalgamation)
> 
> -- 
> Best regards,
> Krystian Bigaj
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

[sqlite] sqlite3_open_v2 vs. *ppDb=NULL

[Krystian Bigaj]

Hi,

Documentation says that:

"The only exception is that if SQLite is unable to allocate memory to hold
the sqlite3 object, a NULL will be written into *ppDb instead of a pointer
to the sqlite3 object"

but I see it's not entirely true. This example below stores NULL in *ppDb
even when (I think) no memory allocation problems occurs:

void TestOpenMisuse(void)
{
  sqlite3 *ppDb;
  int err = sqlite3_open_v2("whatever", , SQLITE_OPEN_CREATE , 0);
  if (ppDb == NULL)
  {
printf("ppDb==NULL, but err==%d, sqlite3_errmsg(ppDb)==%s",
err, sqlite3_errmsg(ppDb));
  }
}


Error code in this case will be err==21 (SQLITE_MISUSE) because
flag SQLITE_OPEN_CREATE cannot be there without SQLITE_OPEN_READWRITE -
which is docummented.
But sqlite3_errmsg(ppDb) will return "out of memory" (because ppDb==NULL),
which can be sometimes little misleading (for me as a SQLite newbie it was
;).

SQLite 3.7.8 (amalgamation)

-- 
Best regards,
Krystian Bigaj
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users