Database System Concepts
7th Edition
ISBN: 9780078022159
Author: Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher: McGraw-Hill Education
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![Example 1: Parent and Child Processes
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
At this point, create a
child process. Now we
have two processes (two
copies of this C program
are running concurrently):
Parent process (rc > 0)
Child process (rc = 0)
starts from here.
Terminate according
to an error.
Wait until the child process
terminates.
int main(int argc, char
{
}
This C program is saved as Process.c.
This C program is available in the
Google Classroom.
*argv[])
printf("hello world (pid:%d)\n", (int) getpid());
int rc = fork();
if (rc < 0) {
// fork failed; exit
fprintf(stderr, "fork failed\n");
exit(1);
} else if (rc == 0) {
To get the PID
// child (new process)
printf("hello, I am child (pid:%d)\n", (int) getpid());
}
return 0;
} else {
// parent goes down this path (original process)
watt(NULL);
printf("hello, I am parent of %d (pid:%d)\n",
rc, (int) getpid());
33](https://content.bartleby.com/qna-images/question/2b9173c6-d6b4-4ba9-960a-2b5f7be4d351/02fa388b-824c-4048-b8bd-f669fa1b2eff/nhds3o_processed.jpeg)
Transcribed Image Text:Example 1: Parent and Child Processes
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
At this point, create a
child process. Now we
have two processes (two
copies of this C program
are running concurrently):
Parent process (rc > 0)
Child process (rc = 0)
starts from here.
Terminate according
to an error.
Wait until the child process
terminates.
int main(int argc, char
{
}
This C program is saved as Process.c.
This C program is available in the
Google Classroom.
*argv[])
printf("hello world (pid:%d)\n", (int) getpid());
int rc = fork();
if (rc < 0) {
// fork failed; exit
fprintf(stderr, "fork failed\n");
exit(1);
} else if (rc == 0) {
To get the PID
// child (new process)
printf("hello, I am child (pid:%d)\n", (int) getpid());
}
return 0;
} else {
// parent goes down this path (original process)
watt(NULL);
printf("hello, I am parent of %d (pid:%d)\n",
rc, (int) getpid());
33
Transcribed Image Text:2. Modify the C program shown in Example 1 in Lecture Note 2 such that the new program will
generate one parent process and three child processes (which all of them created by the parent
process). The output of this program will show each child process PID and its parent process ID.
For example,
A child process with PID: 1001 (parent process PID: 1000).
A child process with PID: 1002 (parent process PID: 1000).
A child process with PID: 1003 (parent process PID: 1000).
Because all of them have the same parent process, their parent process PID is the same.
2.1) Take a screenshot of your program and put here.
2.2) Compile and run your program. Take a screenshot of your program's output and put here.
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