1. 尝试处理普通信号
#include "test.h"
#define MAXSIZE 128
void handler(int signo)
{
if (SIGINT == signo)
{
printf("用户按下了 ctrl + c 键\n");
}
}
int main(int argc, char const *argv[])
{
if (signal(SIGINT, SIG_IGN) == SIG_ERR)
{
perror("signal error");
return -1;
}
if (signal(SIGINT, SIG_DFL) == SIG_ERR)
{
perror("signal error");
return -1;
}
if (signal(SIGINT, handler) == SIG_ERR)
{
perror("signal error");
return -1;
}
while (1)
{
printf("我真的还想再活五百年\n");
sleep(1);
}
return 0;
}
2. 尝试捕获或忽略SIGKILL信号
#include "test.h"
#define MAXSIZE 128
void handler(int signo)
{
if (SIGINT == signo)
{
printf("用户按下了 ctrl + c 键\n");
}
if (SIGKILL == signo)
{
printf("捕获了 SIGKILL 信号\n");
}
}
int main(int argc, char const *argv[])
{
if (signal(SIGKILL, SIG_IGN) == SIG_ERR)
{
perror("signal error");
return -1;
}
if (signal(SIGKILL, handler) == SIG_ERR)
{
perror("signal error");
return -1;
}
if (signal(SIGKILL, SIG_DFL) == SIG_ERR)
{
perror("signal error");
return -1;
}
while (1)
{
printf("我真的还想再活五百年\n");
sleep(1);
}
return 0;
}
3. 使用SIGCHLD信号回收僵尸进程
#include "test.h"
#define MAXSIZE 128
void handler(int signo)
{
if (SIGCHLD == signo)
{
while (waitpid(-1, NULL, WNOHANG) > 0);
}
}
int main(int argc, char const *argv[])
{
if (signal(SIGCHLD, handler) == SIG_ERR)
{
perror("signal error");
return -1;
}
for (int i = 0; i < 10; i++)
{
if (fork() == 0)
{
sleep(1);
exit(EXIT_SUCCESS);
}
}
while (1);
return 0;
}4. 模拟出牌案例
#include "test.h"
#define MAXSIZE 128
void handler(int signo)
{
if (SIGALRM == signo)
{
printf("系统为你随机出了一张牌\n");
alarm(5);
}
}
int main(int argc, char const *argv[])
{
if (signal(SIGALRM, handler) == SIG_ERR)
{
perror("signal error");
return -1;
}
alarm(5);
char ch = 0;
while (1)
{
scanf("%c", &ch);
getchar();
printf("您出的牌为：%c\n", ch);
alarm(5);
}
return 0;
}
5. 验证发送信号函数
#include "test.h"
#define MAXSIZE 128
void handler(int signo)
{
if (SIGUSR1 == signo)
{
printf("造化弄人呀\n");
raise(SIGKILL);
}
}
int main(int argc, char const *argv[])
{
if (signal(SIGUSR1, handler) == SIG_ERR)
{
perror("signal error");
return -1;
}
pid_t pid = fork();
if (pid > 0)
{
while (1)
{
printf("我真的还想再活五百年\n");
sleep(1);
}
}
else if (pid == 0)
{
sleep(5);
printf("我是子进程，我要独立啦！\n");
kill(getpid(), SIGUSR1);
while (1)
{
printf("富贵险中求\n");
sleep(1);
}
}
return 0;
}
6. 消息队列
#include "test.h"
struct msgbuf
{
long mtype;
char mtext[1024];
};
#define MSGSIZE sizeof(struct msgbuf) - sizeof(long)
int main(int argc, char const *argv[])
{
key_t key = 0;
if ((key = ftok("/", 'k')) == -1)
{
perror("ftok error");
return -1;
}
printf("ftok success key = %#x\n", key);
int msgid = -1;
if ((msgid = msgget(key, IPC_CREAT|0664)) == -1)
{
perror("msgget error");
return -1;
}
printf("msgget success msgid = %d\n", msgid);
struct msgbuf sbuf;
while (1)
{
bzero(sbuf.mtext, sizeof(sbuf.mtext));
printf("请输入当前消息的类型：");
scanf("%ld", &sbuf.mtype);
getchar();
printf("请输入消息正文：");
fgets(sbuf.mtext, sizeof(sbuf.mtext), stdin);
sbuf.mtext[strlen(sbuf.mtext) - 1] = 0;
msgsnd(msgid, &sbuf, MSGSIZE, 0);
printf("发送成功\n");
if (strcmp(sbuf.mtext, "quit") == 0)
{
break;
}
}
return 0;
}#include "test.h"
struct msgbuf
{
long mtype;
char mtext[1024];
};
#define MSGSIZE sizeof(struct msgbuf) - sizeof(long)
int main(int argc, char const *argv[])
{
key_t key = 0;
if ((key = ftok("/", 'k')) == -1)
{
perror("ftok error");
return -1;
}
printf("ftok success key = %#x\n", key);
int msgid = -1;
if ((msgid = msgget(key, IPC_CREAT|0664)) == -1)
{
perror("msgget error");
return -1;
}
printf("msgget success msgid = %d\n", msgid);
struct msgbuf rbuf;
while (1)
{
bzero(rbuf.mtext, sizeof(rbuf.mtext));
msgrcv(msgid, &rbuf, MSGSIZE, 1, 0);
printf("收到的消息为：%s\n", rbuf.mtext);
if (strcmp(rbuf.mtext, "quit") == 0)
{
break;
}
}
return 0;
}
7. 使用消息队列完成两个进程间通信
#include "test.h"
struct msgbuf
{
long mtype;
char mtext[1024];
};
#define MSGSIZE sizeof(struct msgbuf) - sizeof(long)
void send(int msgid, long msgtype)
{
struct msgbuf sbuf;
while (1)
{
bzero(sbuf.mtext, sizeof(sbuf.mtext));
printf("请输入消息正文：");
fgets(sbuf.mtext, sizeof(sbuf.mtext), stdin);
sbuf.mtext[strlen(sbuf.mtext) - 1] = 0;
sbuf.mtype = msgtype;
msgsnd(msgid, &sbuf, MSGSIZE, 0);
printf("发送成功\n");
if (strcmp(sbuf.mtext, "quit") == 0)
{
break;
}
}
}
void receive(int msgid, long msgtype)
{
struct msgbuf rbuf;
while (1)
{
bzero(rbuf.mtext, sizeof(rbuf.mtext));
printf("\r");
msgrcv(msgid, &rbuf, MSGSIZE, msgtype, 0);
printf("收到的消息为：%s\n", rbuf.mtext);
printf("请输入消息正文：");
fflush(stdout);
if (strcmp(rbuf.mtext, "quit") == 0)
{
break;
}
}
}
int main(int argc, char const *argv[])
{
key_t key = 0;
if ((key = ftok("/", 'k')) == -1)
{
perror("ftok error");
return -1;
}
printf("ftok success key = %#x\n", key);
int msgid = -1;
if ((msgid = msgget(key, IPC_CREAT|0664)) == -1)
{
perror("msgget error");
return -1;
}
printf("msgget success msgid = %d\n", msgid);
int flag;
puts("请选择：");
puts("1. 主发子收");
puts("2. 主收子发");
printf("请输入：");
scanf("%d", &flag);
getchar();
pid_t pid = fork();
if (pid > 0)
{
if (flag == 1)
{
send(msgid, 1);
}
else if (flag == 2)
{
receive(msgid, 1);
}
}
else if (pid == 0)
{
if (flag == 1)
{
receive(msgid, 2);
}
else if (flag == 2)
{
send(msgid, 2);
}
}
return 0;
}
