fork().c

[shilianzhu]

include <stdio.h>

include <stdlib.h>

include <unistd.h>

// lost wait.h in in orgional function;

include <sys/wait.h>

define SUCCESS 1

define FAILURE 0 /// declare failure to 0

int main( int argc,char *argv[]) // in orgional function, it lost the variable int argc,and char *argv[]
{

// in orgional function argc is !=0, in this should be !=1
if (argc != 1) {

  // the printf should be stderr
    fprintf(stderr, "fork failed.\n");

   // in orgional function is FAILURE, but i change to exit(1);
   exit(1);
}

printf("Hi stranger! I'm (pid:%d)\n", (int) getpid());

// create a new fork(), not knife()
int rc = fork(); //slice off another process

// we delcare failure is 0, so we change to 0 in rc<0
if (rc < 0) {

    // Could not cut another process
    fprintf(stdout, "OS too hard, could not cut.\n");
    exit(0);

// check
} else if (rc == 0) {
fprintf(stderr, "Child can't talk to strangers.\n");
exit(1);

// printf can not print, because above code exit(1) has exit, so from printf to sleep, it does not work in here;

/* printf("Hello, I am child (pid:%d)\n", (int) rc);
sleep(1) ; */

     } else if (rc >0) {

    // we should wait child to end, not parent, it is wait()
    int wc = wait(NULL); 

    printf("Please leave my child alone, I am %d (wc:%d) (pid:%d)\n",
       (int) getpid(), wc,rc);
       // sholude be int getpid(),and rc
}

// return to 0, not success.
return 0;
}

in this function , the code stystle is not good,
missunderstand the fork() libary.