Write the program to implement the system calls getpid() and getppid().

Write the program to implement the system calls getpid() and getppid(). 

Program Algorithm: 

Step 1 : Declare the variables pid , parent pid , child id and grand chil id. 

Step 2 : Get the child id value using system call fork(). 

Step 3 : If child id value is less than zero then print as “error at fork() child”. 

Step 4 : If child id !=0 then using getpid() system call get the process id. 

Step 5 : Print “I am parent” and print the process id. 

Step 6 : Get the grand child id value using system call fork(). 

Step 7 : If the grand child id value is less than zero then print as “error at fork() grand child”. 

Step 8 : If the grand child id !=0 then using getpid system call get the process id. 

Step 9 : Assign the value of pid to my pid. 

Step 10 : Print “I am child” and print the value of my pid. 

Step 11 : Get my parent pid value using system call getppid(). 

Step 12 : Print “My parent's process id” and its value. 

Step 13 : Else print “I am the grand child”. 

Step 14 : Get the grand child's process id using getpid() and print it as “my process id”.

Step 15 : Get the grand child's parent process id using getppid() and print it as “my parent‟s process id 

System Calls Used: 

1.getpid( ) Each process is identified by its id value. This function is used to get the id value of a particular process. 

2.getppid( ) Used to get particular process parent's id value. 

3.perror( ) Indicate the process error. 

Program Code: 

#include<stdio.h> 

#include<unistd.h> 

#include<stdlib.h> 

int main( ) 

{ 

int pid; 

pid=fork( ); 

if(pid== -1) 

{

perror(“fork failed”); 

exit(0); 

} 

if(pid==0) 

{ 

printf(“\nChild process is under execution”); 

printf(“\nProcess id of the child process is %d”, getpid()); 

printf(“\nProcess id of the parent process is %d”, getppid()); 

} 

else 

{ 

printf(“\nParent process is under execution”); 

printf(“\nProcess id of the parent process is %d”, getpid()); 

printf(“\nProcess id of the child process in parent is %d”, pid()); 

printf(“\nProcess id of the parent of parent is %d”, getppid()); 

} 

return(0); 

}