Understanding expected behavior of c language code snippet

Question

I have been given a c language code

#include <stdio.h> 
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#define MAX_BUFFER 256
#define QUIT_STRING "q"

int makeargv(const char *s, const char *delimiters, char ***argvp);

int main (void) {
   char **chargv;
   char inbuf[MAX_BUFFER];

   for( ; ; ) {
      gets(inbuf);
      if (strcmp(inbuf, QUIT_STRING) == 0)
         return 0;
      if ((fork() == 0) && (makeargv(inbuf, " ", &chargv) > 0))
         execvp(chargv[0], chargv);
      wait(NULL);
   }
}

makeargv function which makes tokens out of the string passed as 1st argument (using delimiters passed in 2nd argument) and stores these tokens in the array pointed to by the 3rd argument.

#include <errno.h>
#include <stdlib.h>
#include <string.h>

int makeargv(const char *s, const char *delimiters, char ***argvp) {
   int error;
   int i;
   int numtokens;
   const char *snew;
   char *t;

   if ((s == NULL) || (delimiters == NULL) || (argvp == NULL)) {
      errno = EINVAL;
      return -1;
   }
   *argvp = NULL;                           
   snew = s + strspn(s, delimiters);         /* snew is real start of string */
   if ((t = malloc(strlen(snew) + 1)) == NULL) 
      return -1; 
   strcpy(t, snew);               
   numtokens = 0;
   if (strtok(t, delimiters) != NULL)     /* count the number of tokens in s */
      for (numtokens = 1; strtok(NULL, delimiters) != NULL; numtokens++) ; 

                             /* create argument array for ptrs to the tokens */
   if ((*argvp = malloc((numtokens + 1)*sizeof(char *))) == NULL) {
      error = errno;
      free(t);
      errno = error;
      return -1; 
   } 
                        /* insert pointers to tokens into the argument array */
   if (numtokens == 0) 
      free(t);
   else {
      strcpy(t, snew);
      **argvp = strtok(t, delimiters);
      for (i = 1; i < numtokens; i++)
          *((*argvp) + i) = strtok(NULL, delimiters);
    } 
    *((*argvp) + numtokens) = NULL;             /* put in final NULL pointer */
    return numtokens;
}    

and i need to answer 3 questions which are mentioned below

1. How would the shell implemented in above code will behave when the user gives an invalid command (i.e. a command for which no executable exists)?

2. What would happen if the user gives multiple invalid commands?

3. What happens when the user tries to quit the shell after giving multiple invalid commands.

Here's what i think are the answers to these questions

1. The execv will return an error, but I do not think it will break the code so it will result in two forks trying to read inputs

2. More forks will be created

3. Only one of the forks will quit

Question

Are all of the answers correct? Could any of the answers be improved?

Answer 1

Never have two processes trying to read stdin at once. Race conditions make the resulting environment unusable.

 if (fork() ==0){ 
        if(...)
            execvp();
         _exit(255); /* don't fall back to parent code */
 }