Tech is there any good C programmers on here

is there any good C programmers on here

i'm stuck on a little problem at work. i wrote a class to get me the machine ID for one of 700 database machines on our server farm and when it hits the instance of the class and calls the query it gives me a segmentation fault. i can post the code for the class if anyone can help :sad:

Sure, I'd post it up and see if anyone has an idea on it. Seg faults are pretty much a guarantee that some variable got memory mangled - can be hard to find, might not even have anything to do with the class that it stopped on. Did you run a debugger on it to determine where it stopped? Compiler used - MS Visual Studio, GCC, etc.?

yeah i narrowed it down. do you know much about the mysql c functions. lemme get the code.

Code:

int ServerID::queryid (MYSQL * mData)
{
#define __METHOD__ "queryid()"
sprintf (id,"SHOW VARIABLES LIKE 'server_id'");
        if (mysql_real_query(mData, id, strlen(id)))
        {
                printf ("Query failed: %s\n %s\n", id, mysql_error(mData));
        }
       // else
       // {
                res = mysql_store_result(mData);
       // }
return (0);
#undef __METHOD__
}

from what i can narrow it down to its breaking at the mData which is a struct holding database information. i think its cuz i redeclare it as MYSQL * mData that it may be causing the problem cuz when i run it through a debugger it shows as being blank. I dont know though :superconf

EDIT i use linux and i'm its g++

I haven't played with MySQL stuff - but it is all basically C/C++ stuff. The code snippet you posted here loks like it should not cause errors in some compilers - others will blow up as you have noticed. Linux doens't like null pointer assignments - Borland and Visual Studios will compile fine. Linux will tend to seg fault. Sorry - that wasn't very helpful. might want to try it at some of those guru sites and see what they say.

Good Luck.

i'm assuming you've tried various ways of de-referenceing your mData struct (*, &, etc)

what are the different components of the struct that is being passed in? maybe in order to get this to work properly you need to reference the various parts of it (mData.int1 or mData->int1)

(java/c++ programmer, not as much linux/c experience)

Roxtar: mData is a datahandle tahts not techincally a struct but has struct like properties. its one of the MySQL library functions. i'm still playing with it, if nothing the other guys should be back to work monday so i'll just ask one of them.

fishexpo101: It doesnt if I run it independently. just the fact that it has to be called from an existing API is causing me headaches.

10 A$=w00t
20 PRINT:A$
30 GOTO 10

Apple Basic Bizatch! hehehe.

w00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00t
w00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00t
w00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00t
w00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00t
w00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00tw00t
(ad infinitum)

10 PRINT "w00t"
20 GOTO 10

qbasic and a more elegant solution bizatch!

system.out.println("Hello World");

gay both of you