Programming

Sir, As u told me i had used strace -ppid
and here is the output what I am getting........
it is showing me two pids for a same process........and when I used to strace to them then its showing me following outputs .........

outputs::::::::
[root@localhost New Folder]#strace -p3153
Process 3153 attached - interrupt to quit
write(5, "\0i, I am fine101010\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 100
<unfinished ...>
Process 3153 detached
[root@localhost New Folder]# strace -p3152
Process 3152 attached - interrupt to quit
wait4(-1,

Why is it sitting in wait4()? looks like it thinks the child process should be dead and it's trying to reap it, so it has fallen out of the select loop.

The two pids are one for the main process and another for the child process, which is what we were trying to achieve.

I had put wait in parent ....so that parent will not terminate untill child will not free its resources........If I will not use wait in parent, the parent will terminate and child will be running.........

Yes that's fine, but it's not going to be waiting for input in select if it's blocking in wait4.

your main process should be

Code:

pid_child=fork();

if (!pid_child) 
{ 
     exit(run_child());
}

while (running)
{
      set up fd_sets
      select
      do reads,writes and other stuff
}

kill(pid_child,SIGINT);
waitpid(pid_child...)

you had send me this code.....but I didnt able to understand why you had used p+=i; where p is a char string ......
moreover I am getting more difficulties with code...i.e through pipe read end I am not able to read the data.....
when i check for strace -ppid its showing continously polling (for parent) with select
and child witing for msgrcv()......

Say you want to receive 4096 bytes, but the first read only gets 1024, the next read you do wants to start from where you left off.

Add debugging code to trace what the program is doing.

Use a debugger to step through the code line by line if you have to.

Sir,
now facing problem while using socket comm. and select........my message queue and pipe part is working ....no problem at that side....
my application is continously reading through pipe but when socket comes into picture (my socket is server side (tcp/ip))....it reads only once through socket .....and I had to start client again.

this means that polling is again started with new socket connection......not as per read call.......
so how to implement....tell some steps to follow??????
please guide