Application crash after using mysql_fetch_row - c++

Question

I got a problem regarding simple MySQL function which is mysql_fetch_row when ever I use it, my application will crash with it will go to the point when its executing.
No matter what query I would run it will crash. The core dump says following:
(gdb) bt full
#0 0x2866397f in mysql_store_result () from /usr/home/ld/application
#1 0x28637905 in main () from /usr/home/ld/application
#2 0x08441d3a in CRC_GetCodeSize20 ()
The code looks simple:
int main()
{
MYSQL *conn; // the connection
MYSQL_RES *res; // the results
MYSQL_ROW row; // the results row (line by line)
struct connection_details mysqlD;
mysqlD.server = "localhost"; // where the mysql database is
mysqlD.user = "mysqlusername"; // the root user of mysql
mysqlD.password = "mysqlpassword"; // the password of the root user in mysql
mysqlD.database = "mysql"; // the databse to pick
conn = mysql_connection_setup(mysqlD);
res = mysql_perform_query(conn, "select 1, 2");
printf("Result:\n");
while ((row = mysql_fetch_row(res)) !=NULL)
printf("%s\n", row[0]);
mysql_free_result(res);
mysql_close(conn);
return 0;
}
What is the problem?
edit
mysql_perform_query:
MYSQL_RES* mysql_perform_query(MYSQL *connection, char *sql_query)
{
if (mysql_query(connection, sql_query))
{
printf("MySQL query error : %s\n", mysql_error(connection));
exit(1);
}
return mysql_use_result(connection);
}

Answer 1

Ok. So I have spent quite some time to reproduce this problem. I assume you took the example from this tutorial: http://www.codingfriends.com/index.php/2010/02/17/mysql-connection-example/ since it's exactly the same.
Steps taken:
cd /usr/ports/databases/mysql56-client && make install
Copy pasted the exact code from the above tutorial to test.cpp
g++ -I/usr/local/include/mysql -L/usr/local/lib/mysql -lmysqlclient test.cpp
./a.out
Output:
Mysql tables in database:
entry
old
I used my remote mysql server and a test account. First I made sure I can connect to it via console mysql -h mydomain.com -u test -p
The program seems to work normally. The only thing I noticed is that sometimes it takes 1 second to execute while other times it takes up to 10 seconds for whatever reason.
Built on PC-BSD Isotope Edition (9.1 RELEASE) with up to date port tree.
So now there are 2 people with successful build (me and your friend). Code being the same the only thing I can think of going wrong is the libmysqlclient.so library. Try to update your port tree and do a fresh build. Or maybe try a different version.

Answer 2

You could try viewing the registered *port* using the netstat command , because the reason it might be crashing is, you are using an already registered port for your dbase. Check for that.
Also if you find out working on an already registered port, try changing the port number in the S/w along with that you have to remove the value from the registry as well(regedit) .(Sometimes it uses the shadow port , so need to do that).
Also check for null in your "conn", Somehow maybe you arn't able to initiate a connection. (connection pool exhaustion?? Very doubtful ).