Question

write a C code to create 5 processes Use nice and renice Linux commands to setup different priorities for the 5 processes

Answer 1

code:

#include<stdio.h>
#include <string.h>

int main()
{
int i;
char snum[5];
char pids[10];
int j;
for( i=0,j=5; i<5; i++)
{
if(fork() == 0)
{
char str[100] = "renice -n ";
       // string used to construct rnice command
sprintf(snum, "%d", i+3);
       //getting priority to string
sprintf(pids, "%d", getpid());
       //getting process id to string)
printf("[child] pid %d from [parent] pid %d\n",getpid(),getppid());
strcat(str,snum);
strcat(str," -p ");
strcat(str,pids);
system(str);
       //calling renice command for all processes using system()
exit(0);
}
}
for( i=0; i<5; i++)
wait(NULL);

}

Output: