debian C defunct process.... why

[rabidmonkey]

Hi I have the following code which is basically a function to open a file and load the data into a memory file (bob), i have a basic logging feature (logs to a text file) you will notice the last line "logfile" at which point this is where the program terminates as far as the log is concerned. where it is supposed to drop back to a main function where there is another immediate "logfile" but this never seems to get logged. and 'ps -aux' lists the routine as defunct.

You will notice i have commented the loop out to eliminate the bob memory variable that the data is being loaded into but regardless it does not seem to drop back to the main and the next log statement.

I am stumped here. i like to think of programming as a puzzle, but this has had me going for a couple of months now due to the complexity of this program in relation to my skills.

I would much appreciate as with my last posts if someone could 'hint' to me the direction i should be researching in. even beter if someone could point me to a good resource on how to troubleshoot defuncts on gcc under linux.

Thanks in advance guys and gals....

Rabid Monkey...

int loadgeneticfile()
{
    logfile("loadgeneticpair");
    char fnamegen[40];
    sprintf(fnamegen,"%s%s%s","./Database/",GLOBAL_alivefilerec.name,".gen");
    logfile(fnamegen);
    FILE * geneticfileP;
    long p=2000;
    if (geneticfileP = fopen (fnamegen,"r")) {flockfile(geneticfileP);logfile("loading");
/*        for (p=2000;p<GLOBAL_alivefilerec.size-1;p++) {
            fread(&childlogicrec, sizeof(childlogicrec), 1, geneticfileP);
            bob[p].IO=childlogicrec.portIO;
            bob[p].logik=childlogicrec.logictype;
            bob[p].output=childlogicrec.output;
            bob[p].inputA=childlogicrec.inputA;
            bob[p].inputB=childlogicrec.inputB;
 
 
        }*/
        funlockfile(geneticfileP);fclose(geneticfileP);
        } else {logfile("failed");}
    logfile("end loadgenticpair.....");
}

[rabidmonkey]

sorry here as an example of the log file cat from terminal...


granit:/mnt/md0/home/damian/ai/tree/Database# cat 1191276062.1016000202.log

2 reset daycount
3 loadgeneticpair
4 ./Database/1191276062.1016000202.gen
5 loading
6 end loadgenticpair.....granit:/mnt/md0/home/damian/ai/tree/Database#

[RRick]

A <defunct> program in unix is knowned as a "zombie" program. The creation of a zombie process takes a couple of things to happen, but basically the program is dead, but an entry in the process table remains. This entry usually lasts until the machine is rebooted. Check out http://en.wikipedia.org/wiki/Zombie_process for more details.

Sooo, it looks like you process/program died before it could print out the next log. That is a good place to begin your search. These problems can be tough to debug.

The best way to find the problem is to have the debugger find the problem. This means the program has to be compiled with the debugger info enabled and you then attach the debugger to the program. Gdb can attach to a process id or you can have the parent start the child program in the debugger. The second method works well if the parent is using the system command. If so, start the debugger in an xterm (i.e. xterm -e gdb programName) when the xterm shows up run the program with the correct parameters.

[rabidmonkey]

Hi RRick,

Thanks Very much for your help, this will give me lots to get my teeth into

Thanks again

RabidMoney