sleep.c

This is to bulid a sample linux shell.

#include<stdio.h>
#include<signal.h>
#include<sys/time.h>
#include<errno.h>
#include<setjmp.h>
#include<string.h>
#include<stdlib.h>
#include<unistd.h>
unsigned int sleep(unsigned int );//returns:0 or number of seconds
  
main(int argc,char **argv)
{
	int n,i;
	if(argc<2)
	{
		fprintf(stderr,"Usage: %s <period(S)>\n");
		exit(0);
	}

	for(i=1;i<argc;i++)
	{
		if(sscanf(argv[1],"%d",&n)!=1)
		{ printf("Not a valid number\n"); exit(225);  }
		sleep(n);
		n=0;
	}
	return 0;
}