Thread: Problem with MYSQL

I am using the Mysql C api and the DevPack made for this. But when I am using this code, I always get an Illegal Operation message when running the program:

Code:

#include <windows.h>
#include <iostream>
#include <mysql/mysql.h>

using namespace std;

int main()
{
    char *host = "sql1.badblock.com";
    char *user = "theuser";
    char *pass = "thepassword";
    char *db = "thedb";
    MYSQL_RES *result;
    MYSQL *res;

    MYSQL *sock;
    sock = mysql_init(0);
    if (sock) cout << "sock handle ok!" << endl;
    else {
         cout << "sock handle failed!" << endl;
         return EXIT_FAILURE;
    }

    if (res=mysql_real_connect(sock, host, user, pass, db, 0, NULL, 0))
         cout << "connection ok!" << endl;
    else {
         cout << "connection failed!" << endl;
         return EXIT_FAILURE;
    }
    
    mysql_query(res,"SELECT address FROM music WHERE pass=euro8");
    cout<<"Query done!";
    result=mysql_store_result(res);
    cout<<"Store result done!";
MYSQL_FIELD *field;
cout<<"mysql field done!";

while(field = mysql_fetch_field(result))
{
cout<<"in while!";
    cout<<field;
}
cout<<"while done!";
cin.get();
    mysql_close(sock);

    return EXIT_SUCCESS;
}

So I added some couts to see how far the program got, before illegal operation message appears. The last cout displayed is mysql field done. Any ideas?

As a first step, add a << flush to each of your debug printing lines to make sure they are printed immediatly and not buffered and forgotten when your app crashes:

Example:

Code:

cout << "in while" << flush;

What gets printed when you cout the field pointer ? I don't know the API, but maybe

Code:

cout << field->name << flush;

is more appropriate.

If both doesn't help, your best bet is getting a debugger. Does Dec-Cpp have one ?

Well I just tested your program I get a connection failed

>>result=mysql_store_result(res);

Your not checking result for NULL.

>>SELECT address FROM music WHERE pass=euro8

Might that be "SELECT address FROM music WHERE pass='euro8'"

??

It doesnt help, still I get the illegal operation message

Originally Posted by maxorator

It doesnt help, still I get the illegal operation message

Have you tried running you're query through the MySQL Query Browser?

Does it return the recordset you expect?

You also need to check the result of mysql_query to see if it is non zero.