Programming

i was searching on the net have found a couple of sample programs and was wondering if some could tell me what they do cheers.

main()
{
printf("Executing ls\n");
execl("/bin/ls","ls","-l", (char *)0);
perror("execl failed to run ls");
exit(1);
}



main()
{
int i;

i = fork();
if (i == 0)
{
printf("Child. getpid() = %d, getppid() = %d\n", getpid(), getppid());
sleep(5);
printf("After sleeping. getpid() = %d, getppid() = %d\n",
getpid(), getppid());
}
else
{
printf("Parent exiting now\n");
}
}


thanks in advance guys

the first one executes the command /bin/ls .
i have an idea what the second one does but im not really sure. they both are safe to run so if you have a working compiler you should run them to find out.

ruff, are you sure these are not homework problems? The both seem like the kind of problems that a teacher would ask students to analyze ..... especially the forking template.

Could you provide the URL(s) of where you found these on the net? Thanks.

no actaully it is real i was searching on the internet to help me learn more about c due to me being only new to coding, and found these code examples and they looked more advanced and interesting so was wondering what they meant mate.

http://angelfire.lycos.com/clone2/coding/index.html

For the first one, execl() is a function that will cause the program to overlayed by a different program. It's still same process, but it's now a different program. If execl() works, then we will never return from it. So if we do return, something went wrong. That's why it has that perror() and an exit(1).

The second one uses fork() which creates a second process. Both processes will return from the fork(). The child process will see a return code of 0. And the parent will see a return code of a positive integer which is the pid of the newly created child. So by testing that return code, the programmer can make the parent and the child do something different.

thanks guys appreciate it