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clk.c
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clk.c
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/*
* This file is done for you.
* Probably you will not need to change anything.
* This file represents an emulated clock for simulation purpose only.
* It is not a real part of operating system!
*/
#include "Header_File/headers.h"
int shmid;
/* Clear the resources before exit */
void cleanup(int signum)
{
shmctl(shmid, IPC_RMID, NULL);
printf("clk: Clock terminating!\n");
exit(0);
}
/* This file represents the system clock for ease of calculations */
int main(int argc, char * argv[])
{
printf("clk: Clock starting\n");
signal(SIGINT, cleanup);
int clk = 0;
//Create shared memory for one integer variable 4 bytes
shmid = shmget(SHKEY, 4, IPC_CREAT | 0644);
if ((long)shmid == -1)
{
perror("clk: Error in creating shm!");
exit(-1);
}
int * shmaddr = (int *) shmat(shmid, (void *)0, 0);
if ((long)shmaddr == -1)
{
perror("clk: Error in attaching the shm in clock!");
exit(-1);
}
*shmaddr = clk; /* initialize shared memory */
while (1)
{
sleep(1);
(*shmaddr)++;
}
}