I think problem is in use char * as parameter in push function. For that
reason I use std::string always.
Look, in callback2 SQLite pass char ** - array of char*. But when your
code leave callback2 SQLite might errase that array and then all char*
will garbage. But when in push method you will pass const std::string &
-- char* will transform into std::string and you will not lose any data.
Or event you can obviosly call ctor of std::string like
q->push( atoi(argv[0] ),atoi(argv[1] ),atoi(argv[2] ), std::string(
argv[3] ), std::string( argv[4] ) );
and push method then will looks like this:
void QuestionDB::push( int b, int c, int v, const std::string & q, const
std::string & a )
{
...
}
P.S. Try don't use char* in C++ code. Use std::string instead. And when
you need char* you can transform std::string into char* with c_str()
method of std::string.
Stephen Sutherland wrote:
Igor I tried your solution and can't get it working .
Here is my code.
The STRANGE problem that I am having is that when it adds to the vector at position 1, the vector contains the object.
But when it adds to vector at position 2 using push_back - for some reason the contents at vector 1 is garbage.
then when it adds to vector at position 3 using push_back - for some reason position 3 is garabage ?
the errors in this situation doesn't seem to follow much logic ? but it's consistent.
for example if i run this code and it uses push 4 times, position 1 and 3 might have garbase while position 2 will have the same contents as position 4 ? ?
this is some weird stuff i haven't seen before.
I'm wondering if the problem is due to the scope of either my QuestionDBStruct or my vector .
=================================================
static int callback2(void *NotUsed, int argc, char **argv, char **azColName)
{
int i;
for(i=0; i<argc; i++)
{
printf("%i. %s = %s\n", i, azColName[i], argv[i] ? argv[i] : "NULL");
}
QuestionDB* q = (QuestionDB*)NotUsed;
q->push(c );
return 0;
};
QuestionDB::QuestionDB()
{
};
void QuestionDB::push(int b, int c, int v, char* q, char* a)
{
QuestionDBStruct qbs;
qbs.bible_book =1;
qbs.bible_chapter =2;
qbs.bible_verse =3;
qbs.bible_answer ="test";
qbs.bible_question =q;
printf("\n****** push called ************\n");
vecQuestions.push_back(qbs);
for(int x = 0 ; x < vecQuestions.size(); x++)
printf("\nvecQuestion[%i] = %s \n", x,
((QuestionDBStruct)vecQuestions[x]).bible_question );
printf("\n*******************************\n");
}; ========================================================
Igor Mironchick <[EMAIL PROTECTED]> wrote:
If I understand you right then try it:
static int add_value( void *st, int, char **value, char ** )
{
storage_t * storage = (storage_t*) st;
st->push( value[ 0 ] );
return SQLITE_OK;
};
class storage_t {
public:
storage_t()
: m_db( 0 )
{
sqlite3_open( "your_database.db", &m_db );
};
virtual ~storage_t()
{
sqlite3_close( m_db );
};
void push( const std::string & v )
{
m_buff.push_back( v );
}
void read_table()
{
sqlite3_exec( m_db, "SELECT * FROM some_table",
add_value, this, NULL );
}
private:
sqlite3 * m_db;
std::vector< std::string > m_buff;
};
This is very simple example, but it can help you I think.
Stephen Sutherland wrote:
Hi
I am using the 'quick start' C-styled code for sqlite3
http://www.sqlite.org/quickstart.html
I think I'm running into a problem trying to put it in classes to make it somewhat object oriented. So I'm asking for help about how to make it object-oriented - or to confirm whether what I'm doing is object oriented.
Here is the code:
[code]
//callback function
static int callback(void *NotUsed, int argc, char **argv, char **azColName)
{
int i;
for(i=0; i> printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
}
printf("\n");
return 0;
};
// this callback is referenced here.
void MyClass::executeSQLStatement()
{
rc = sqlite3_exec(db, "select * from table1" , callback, 0, &zErrMsg);
};
[/code]
However I am trying to add a vector in the callback function to store the
results. When I put the vector in it seems I am forced to do something like
this:
[code]
vector vecX;
static int callback(void *NotUsed, int argc, char **argv, char **azColName)
{
int i;
for(i=0; i> printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
}
vecX.push_back(argv[3]);
printf("\n");
return 0;
};
[/code]
Now this doesn't seem object oriented ?
Nor do I understand how I would access this vector from other classes ?
And I don't know how this vector which I created can be considered part of the class ? it seems to me to only have page scope.
Any advice on how to make my vector object oriented or accessible by other classes ?
Thanks in Advance
Stephen
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Regards,
Igor Mironchick,
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