Linux C Get implementation code for process exit value _c language

as shown in the following code:

Copy Code code as follows:

#include <stdio.h>
#include <stdlib.h>
#include < String.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#incl Ude <errno.h>
int main (int argc, char *argv[])
{
 pid_t pid;
 int Stat;
 int Exit_code;

 pid = fork ();
 if (pid = = 0)
 {
  sleep (3);
  exit (5);
 }
 else if (PID < 0)
 {
  fprintf (stderr, fork failed:%s), strerror (errno));
  return-1;
 }

 wait (&stat);  //waits for a child process to end
 if (wifexited) stat If the subprocess passes through return, exit,  // Normal end, wifexited () returns True
 {
  exit_code = wexitstatus (stat);
  printf ("Child ' s Exit_code:%d\n", Exit_code);
 }

 return 0;
}

Reference: "Man 2 Wait"