/*-------------------------------------------------------------------*/
/* textforkexecwait.c                                                */
/* The fork, exec, and wait system calls.                            */
/*-------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wait.h>

#define MAX_COMMAND_SIZE 1024

int main(int argc, char *argv[])
{
   int iPid;
   int iStatus;
   char pcCommandName[MAX_COMMAND_SIZE];

   printf("%% ");
   scanf("%s", pcCommandName);
   while (strcmp(pcCommandName, "exit") != 0)
   {
      fflush(NULL);
      iPid = fork();
      if (iPid == -1) {perror(argv[0]); return 1; }

      if (iPid == 0)
      {
         /* This code is executed by only the child process. */
         char *ppcArgv[2];

         ppcArgv[0] = pcCommandName;
         ppcArgv[1] = NULL;

         execvp(ppcArgv[0], ppcArgv);
         perror(argv[0]);
         exit(1);
      }

      /* Wait for the child process to finish. */
      iPid = wait(&iStatus);
      if (iPid == -1) {perror(argv[0]); return 1; }

      printf("Command executed with status %d.\n\n", WEXITSTATUS(iStatus));

      printf("%% ");
      scanf("%s", pcCommandName);
   }

   return 0;
}

/* Sample execution:

$ gcc -Wall -ansi -pedantic -o hello hello.c
$ gcc -Wall -ansi -pedantic -o testforkexecwait testforkexecwait.c
$ testforkexecwait
% hello
hello process (29693)
Command executed with status 0.

% date
Tue Apr 20 21:50:29 EDT 2004
Command executed with status 0.

% xxx
testforkexecwait: No such file or directory
Command executed with status 1.

% exit
$

*/