linux 进程间通信--systemV 消息队列 实例

#include<stdlib.h>
#include<stdio.h>
#include<unistd.h>
#include<string.h>
#include <sys/wait.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>
#include <errno.h>
#include <sys/stat.h>
#define MAX_TEXT 512
struct my_msg_st
{int my_msg_type;char msg_text[MAX_TEXT];
};
#define MSG_FILE "/wlan/configap/mkwrielessconfig.sh"
#define MSG_FLAG IPC_CREAT|S_IRUSR|S_IWUSR
int msgid=0;
void signalHandler(int sig)
{
#if 0switch (sig){case SIGINT:case SIGTERM:if (msgctl(msgid, IPC_RMID, NULL) == -1){perror("msgget() failed to delete old queue");}else{printf("remove msgid:%d\n",msgid);}}
#endifprintf("main process exit\n");exit(0);
}
int checkSelect(int handfd,char *rwflag)
{int ret, retval=0xff;fd_set readfds, writefds;struct timeval	timeout;FD_ZERO(&readfds);FD_ZERO(&writefds);static int numfds = 0;if (handfd >= numfds){numfds = handfd + 1;              /* Record maximum fd + 1 */}if (strchr(rwflag, 'r') != NULL){FD_SET(handfd, &readfds);}if (strchr(rwflag, 'w') != NULL){FD_SET(handfd, &writefds);}while (1){/*设置阻塞时间为5秒*/timeout.tv_sec = 0;timeout.tv_usec = 20;retval =0xff;ret = select(numfds, &readfds, &writefds, NULL, &timeout);switch (ret){case 0://exit(0);break;case -1:perror("select");exit(1);break;default:if (FD_ISSET(handfd, &readfds)){retval =0;FD_CLR(handfd, &readfds);FD_SET(handfd, &readfds);}if(FD_ISSET(handfd, &writefds)){retval =1;FD_CLR(handfd, &writefds);FD_SET(handfd, &writefds);}break;}// printf("time out1--------------\n");return retval;}
}int main(int argc,char *argv[])
{int running=1;int childPid;struct my_msg_st some_data;int fd=0;char buffer[BUFSIZ];int msg_to_receive=2;int stat_val;key_t key;if((key=ftok(MSG_FILE,'a'))==-1){fprintf(stderr,"Creat Key Error：%s\n\n",strerror(errno));exit(1);}if((msgid=msgget(key,MSG_FLAG)) == -1){perror("msgget");exit(0);}
#if 0childPid=fork();if( childPid < 0 ){exit(0);}else if( childPid == 0 ){while(running){if(msgrcv(msgid,(void *)&some_data,BUFSIZ,msg_to_receive,0)==-1){perror("msgrcv");exit(EXIT_FAILURE);}printf("\nreceiver mssage:%s",some_data.msg_text);if(strncmp(some_data.msg_text,"end",3)==0){running=0;kill(getppid(),SIGINT);}}}else{#if 1struct sigaction sa;sa.sa_handler = signalHandler;sa.sa_flags = 0;	/* Interrupt system calls */sigemptyset(&sa.sa_mask);sigaction(SIGINT, &sa, NULL);sigaction(SIGQUIT, &sa, NULL);#endifwhile(running){printf("Enter the mssage to send:");fgets(buffer,BUFSIZ,stdin);some_data.my_msg_type=1;strcpy(some_data.msg_text,buffer);if((msgsnd(msgid,(void *)&some_data,MAX_TEXT,0))==-1){perror("msgsnd");exit(EXIT_FAILURE);}if(strncmp(buffer,"end",3)==0){running=0;printf("kill child pid:%d getpid:%d\n",childPid,getpid());kill(childPid,SIGINT);}}}printf("pid:%d getpid:%d\n",childPid,getpid());waitpid(childPid, &stat_val, 0);if (WIFEXITED(stat_val)){printf("Child exited with code %d\n", WEXITSTATUS(stat_val));}else if (WIFSIGNALED(stat_val)){printf("Child terminated abnormally, signal %d\n", WTERMSIG(stat_val));}
#endif#if 1while(1){if(checkSelect(fd,"r")==0){printf("Enter the mssage to send:");fgets(buffer,BUFSIZ,stdin);some_data.my_msg_type=1;strcpy(some_data.msg_text,buffer);if((msgsnd(msgid,(void *)&some_data,MAX_TEXT,0))==-1){perror("msgsnd");exit(EXIT_FAILURE);}if(strncmp(buffer,"end",3)==0){running=0;}}if(running){if(msgrcv(msgid,(void *)&some_data,BUFSIZ,msg_to_receive,IPC_NOWAIT)==-1){}else{printf("\nreceiver mssage:%s",some_data.msg_text);if(strncmp(some_data.msg_text,"end",3)==0){running=0;}}}if(running==0){if(msgctl(msgid,IPC_RMID,0)==-1){if(EINVAL == errno){msgctl(msgid,IPC_RMID,0);exit(EXIT_FAILURE);}}else{printf("remove msgid:%d\n",msgid);}exit(0);}}
#endifreturn 0;
}

2：消息发送端

#include<stdlib.h>
#include<stdio.h>
#include<unistd.h>
#include<string.h>
#include <sys/wait.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/msg.h>
#include <errno.h>
#include <sys/stat.h>
#define MSG_FILE "/wlan/configap/mkwrielessconfig.sh"
#define MSG_FLAG IPC_CREAT|S_IRUSR|S_IWUSR
int msgid=0;
#define MAX_TEXT 512
struct my_msg_st
{int my_msg_type;char msg_text[MAX_TEXT];
};
void signalHandler(int sig)
{
#if 0printf("-----------------------\n");if(SIGINT == sig){if (msgctl(msgid, IPC_RMID, NULL) == -1){perror("msgget() failed to delete old queue");}else{printf("remove msgid:%d\n",msgid);}}
#endifprintf("main process exit\n");exit(0);
}
int main(int argc,char *argv[])
{int running=1;int childPid;struct my_msg_st some_data;char buffer[BUFSIZ];int msg_to_receive=1;int stat_val;key_t key;if((key=ftok(MSG_FILE,'a'))==-1){fprintf(stderr,"Creat Key Error：%s\n\n",strerror(errno));exit(1);}if((msgid=msgget(key,MSG_FLAG)) == -1){perror("msgget");exit(0);}childPid=fork();if( childPid < 0 ){exit(0);}else if( childPid == 0 ){while(running){if(msgrcv(msgid,(void *)&some_data,BUFSIZ,msg_to_receive,0)==-1){perror("msgrcv");exit(EXIT_FAILURE);}printf("\nreceiver mssage:%s",some_data.msg_text);if(strncmp(some_data.msg_text,"end",3)==0){running=0;kill(getppid(),SIGINT);}}}else{#if 1struct sigaction sa;sa.sa_handler = signalHandler;sa.sa_flags = 0;	/* Interrupt system calls */sigemptyset(&sa.sa_mask);sigaction(SIGINT, &sa, NULL);sigaction(SIGQUIT, &sa, NULL);#endifwhile(running){printf("Enter the mssage to send:");fgets(buffer,BUFSIZ,stdin);some_data.my_msg_type=2;strcpy(some_data.msg_text,buffer);if((msgsnd(msgid,(void *)&some_data,MAX_TEXT,0))==-1){perror("msgsnd");exit(EXIT_FAILURE);}if(strncmp(buffer,"end",3)==0){running=0;printf("kill child pid:%d getpid:%d\n",childPid,getpid());kill(childPid,SIGINT);}}}printf("pid:%d getpid:%d\n",childPid,getpid());waitpid(childPid, &stat_val, 0);if (WIFEXITED(stat_val)){printf("Child exited with code %d\n", WEXITSTATUS(stat_val));}else if (WIFSIGNALED(stat_val)){printf("Child terminated abnormally, signal %d\n", WTERMSIG(stat_val));}if(msgctl(msgid,IPC_RMID,0)==-1){if(EINVAL == errno){msgctl(msgid,IPC_RMID,0);exit(EXIT_FAILURE);}}else{printf("remove msgid:%d\n",msgid);}return 0;
}