Re: [sqlite] How do I check if the DB is open?

[Dan Kennedy]

On 12/14/2016 10:56 AM, Igor Korot wrote:
Keith,
On Tue, Dec 13, 2016 at 8:34 PM, Keith Medcalf <kmedc...@dessus.com> wrote:
     int res = sqlite3_close( m_db );
     if( res == SQLITE_OK )
         m_db = NULL;
     else
     {
// error handling
     }
#ifdef DEBUG
     sqlite3_stmt *statement = sqlite3_next_stmt( m_db, NULL );
     if( statement )
         const char *query = sqlite3_sql( statement );
#endif
Is it OK to pass NULL as a first parameter to sqlite3_next_stmt()?
Upon checking the documentation it looks like the call will fail if
m_db is NULL.

Why run the sqlite3_next_stmt() call if sqlite3_close() returns 
SQLITE_OK. In that case you already know there are no unfinalized 
statements. i.e. can you not put the sqlite3_next_stmt() checks in the 
"// error handling" block above?

Dan.





Thank you.

Then you simply do:

if (!m_db)
{
// the pointer does not point to anything error handling
}

or conversely:

if (m_db)
{
// do stuff with the connection
}
else
{
// database is not open error
}


-----Original Message-----
From: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org]
On Behalf Of Igor Korot
Sent: Tuesday, 13 December, 2016 17:55
To: Discussion of SQLite Database; General Discussion of SQLite Database
Subject: [sqlite] How do I check if the DB is open?

Hi, ALL,
I'm using following code to check for errors in debug mode:

     int res = sqlite3_close( m_db );
     if( res != SQLITE_OK )
     {
// error handling
     }
#ifdef DEBUG
     sqlite3_stmt *statement = sqlite3_next_stmt( m_db, NULL );
     if( statement )
         const char *query = sqlite3_sql( statement );
#endif

However the call to sqlite3_close() make the 'm_db' pointer invalid if
everything is successful and hence the sqlite3_next_stmt() crashes.

How do I properly check if the DB is still open?
Or maybe I should put the code inside #ifdef....#endif before DB closing?

Thank you.
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