父进程等待子进程退出

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
int main()
{
pid_t pid;
int cnt = 0;
pid = fork();
if(pid>0) {
wait(NULL);
while(1) {
printf(“this is father print,pid = %d\n”,getpid());
sleep(1);
printf(“cnt = %d\n”,cnt);
}
}
else if(pid == 0) {
while(1) {
printf(“this is child print,pid = %d\n”,getpid());
sleep(1);
cnt++;
if(cnt == 3) {
exit(0);
}
}
}
return 0;
}
2.
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
int main()
{
pid_t pid;
int cnt = 0;
int status = 10;
pid = fork();
if(pid>0) {
wait(&status);
printf(“child quit,child status = %d\n”,WEXITSTATUS(status));
while(1) {
printf(“this is father print,pid = %d\n”,getpid());
sleep(1);
printf(“cnt = %d\n”,cnt);
}
}
else if(pid == 0) {
while(1) {
printf(“this is child print,pid = %d\n”,getpid());
sleep(1);
cnt++;
if(cnt == 3) {
exit(0);
}
}
}
return 0;
}
3.
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
int main()
{
pid_t pid;
int cnt = 0;
int status = 10;
pid = fork();
if(pid>0) {
printf(“this is father print,pid = %d\n”,getpid());
}
else if(pid == 0) {
while(1) {
printf(“this is child print,pid = %d,my father pid = %d\n”,getpid(),getppid());
sleep(1);
cnt++;
if(cnt == 5) {
exit(0);
}
}
}
return 0;
}
4.