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fork() and wait()

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Join Date: Dec 2006

Posts: 35

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rwagnes

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fork() and wait()

Mar 25th, 2007

I am supposed to create a chain of N processes, where N is the command line parameter. Each process creates a child process, prints out its own PID and its parent's PID, and then waits for its child to terminate by calling the wait() function.

Here is my code:

 Help with Code Tags 
 c Syntax (Toggle Plain Text) 
#include <stdio.h>
int main(int argc, char *argv[])
{
 
int number = atoi(argv[1]);
int i;
int pid;
 
for (i=0; i<number-1; i++)
{
 
pid=fork();
if (pid==0)
wait();
 
else
{
printf("I am the child\n");
printf("my pid=%d\n", getpid());
printf("and my parent pid=%d\n", getppid());
}
 
}
}
#include <stdio.h>
int main(int argc, char *argv[])
{
 
int number = atoi(argv[1]);
int i;
int pid;
 
for (i=0; i<number-1; i++)
{
 
pid=fork();
if (pid==0)
wait();
 
else
{
printf("I am the child\n");
printf("my pid=%d\n", getpid());
printf("and my parent pid=%d\n", getppid());
}
 
}
}

Any ideas why it's not working properly?

Example output:

[balhoffe1@gator labfork]$ ./lab2 4
I am the child
my pid=6381
and my parent pid=5670
I am the child
my pid=6381
and my parent pid=5670
I am the child
my pid=6382
and my parent pid=6381
I am the child
my pid=6381
and my parent pid=5670
[balhoffe1@gator labfork]$ I am the child
I am the child
my pid=6384
and my parent pid=1
my pid=6382
and my parent pid=1
I am the child
my pid=6383
and my parent pid=1

Last edited by ~s.o.s~; Mar 25th, 2007 at 1:50 pm. Reason: Added code tags, learn to use them.