Homework & Coursework Questions

Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!

1. The problem statement, all variables and given/known data:

Modify the program exec_in.c to obtain the same result but replacing the functions sleep and system for system calls. You can use exit, exec*, pause, alarm, etc. The new program will be called exec_in2.c and keep the original program syntax

2. Relevant commands, code, scripts, algorithms:

Code:

#include <stdlib.h>  
#include <stdio.h>  
#include <string.h>  
#include <errno.h>  
#include <unistd.h>   
#include "rutines.h"  

 int main(int argc, char *argv[])  
{      
      char cmd[256];
      int a;

      if (argc<2)
          Error("Insufficient arguments: exec_in <sec> <cmd> [args...]");

     sleep(atoi(argv[1]));
     cmd[0]='\0';

     for(a=2;a<argc;a++)
     {
          strcat(cmd,argv[a]);
          strcat(cmd," ");
      }

     system(cmd);
     exit(0);
}

3. The attempts at a solution (include all code and scripts):

I'm not sure what system call I need to solve the problem, I think that I need to use alarm but I don't know how to use correctly that, I never used system calls in C before, also I have only been using linux one week and I'm really lost.

4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course): Centre d'estudis Roca, Barcelona, Spain, Mariano Torres


Note: Without school/professor/course information, you will be banned if you post here! You must complete the entire template (not just parts of it).

I use ubuntu 12.04 64 bits

The first place too look would be the man pages. System calls are in section 2 - e.g. man 2 alarm (or look on this web site - https://www.unix.com/man-page/linux/2/alarm/).

execl would probably be the system call you want.

Thanks Corona I will search about that.