execlp2.c

/*
Example from
https://chat.stackexchange.com/transcript/message/59383566#59383566

You may use tput. Examples: tput >/dev/null (status == 2, usage
error), TERM=foo tput >/dev/null (status == 3, no information for
the terminal type), tput foo >/dev/null (status == 4, unknown
capability). It can also return 1, which POSIX says is
"unspecified" and historically used to tell the terminal doesn't
have the specified capability (e.g. TERM=vt100 tput setaf
>/dev/null); notably, in this case the exit status is ≠ 0, but no
error message is printed out.
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>

int main(void)
{
  //pid_t parent = getpid();
  pid_t pid = fork();

  if (pid == -1)
    {
      // error, failed to fork()
    }
  else if (pid > 0)
    {
      int status;
      int waitreturnval = waitpid(pid, &status, 0);
      if(waitreturnval > 0)
	printf("wait exited with process ID of the terminated child %d\n", waitreturnval);
      else if(waitreturnval == -1)
	printf("wait exited with error");
      else if(waitreturnval == 0)
	printf("wait exited with code %d\n", waitreturnval);
      if(WIFEXITED(status))
        printf("Child's exit code %d\n", WEXITSTATUS(status));
      else
        printf("Child did not terminate with exit\n");
    }
  else
    {
      //execl("/bin/sh", "bin/sh", "-c", "./nopath", "NULL");
      //execlp("ls", "ls", "-la", "zarko.tex", (char *)0);
      //execlp("lsxx", "lsxx", "-la", "zarko.tex", (char *)0);
      //int fd = open("/dev/null", O_WRONLY | O_CLOEXEC);
      //int setenv(const char *name, const char *value, int rewrite);

      /* setenv("TERM", "foo", 1); */
      //int fd = open("/dev/null", O_WRONLY | O_CLOEXEC);
      //dup2(fd, 1);
      //execlp("tput", "tput", "foo", (char *)0);
      //execlp("sh", "sh", "-c", "./nopath", (char *)NULL);
      //execl("/bin/sh", "bin/sh", "-c", "./nopath", "NULL");
      //execlp("sh", "sh", "-c", "./nopath", NULL);
      //execlp("sh", "sh", "-c", "exit 17", (char *)NULL)
      execlp("lsx", "lsx", "-la", "zarko.tex", (char *)NULL);
      printf("Continues past execlp call.\n");
      //_exit(EXIT_FAILURE);   // exec never returns
      //_exit(21930);   // exec never returns
      _exit(132);   // exec never returns
    }
}