SQLite Forum

I can run sqlite3_exec () successfully for the first time, then continue run sqlite3_exec() returns nothing. 

static int callback(void *ret, int argc, char **argv, char **azColName)
{
    int i;
    static int len = 0;
    for(i=0; i<argc; i++){
        len += snprintf ( ret + len, CONTENT_SIZE - len ," %s ",argv[i] ? argv[i] : "NULL" ); 
    }
    len += snprintf ( ret + len, CONTENT_SIZE - len ,"<br>" ); 
    return 0;
}

main()
{
char ret[8096];
rc = sqlite3_exec(db, sql, callback, ret, &zErrMsg);

}

Can you please advise some suggestions ? 

Thanks,
Forrest