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Linux进程通信例子
1.共享内存
使用:mmap- /*-------------map_normalfile1.c-----------*/
- #include <sys/mman.h>
- #include <sys/types.h>
- #include <fcntl.h>
- #include <unistd.h>
- typedef struct{
- char name[4];
- int age;
- }people;
- main(int argc, char** argv) // map a normal file as shared mem:
- {
- int fd,i;
- people *p_map;
- char temp;
-
- fd=open(argv[1],O_CREAT|O_RDWR|O_TRUNC,00777);
- lseek(fd,sizeof(people)*5-1,SEEK_SET);
- write(fd,"",1);
-
- p_map = (people*) mmap( NULL,sizeof(people)*10,PROT_READ|PROT_WRITE,
- MAP_SHARED,fd,0 );
- close( fd );
- temp = 'a';
- for(i=0; i<10; i++)
- {
- temp += 1;
- memcpy( ( *(p_map+i) ).name, &temp,2 );
- ( *(p_map+i) ).age = 20+i;
- }
- printf(" initialize over \n ");
- sleep(10);
- munmap( p_map, sizeof(people)*10 );
- printf( "umap ok \n" );
- }
- /*-------------map_normalfile2.c-----------*/
- #include <sys/mman.h>
- #include <sys/types.h>
- #include <fcntl.h>
- #include <unistd.h>
- typedef struct
- {
- char name[4];
- int age;
- }people;
- void main(int argc, char** argv) // map a normal file as shared mem:
- {
- int fd,i;
- people *p_map;
- fd=open( argv[1],O_CREAT|O_RDWR,00777 );
- p_map = (people*)mmap(NULL,sizeof(people)*10,PROT_READ|PROT_WRITE,
- MAP_SHARED,fd,0);
- for(i = 0;i<10;i++)
- {
- printf( "name: %s age %d;\n",(*(p_map+i)).name, (*(p_map+i)).age );
- }
- munmap( p_map,sizeof(people)*10 );
- }
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3.管道
mkfifo
- #include<stdio.h>
- #include<stdlib.h>
- #include<string.h>
- #include<fcntl.h>
- #include<sys/types.h>
- #include<sys/stat.h>
- int main(int argc,char *argv[])
- {
- int fd;
- char buf[20] = "hello world!!!/n";
- if((mkfifo("my_fifo", O_CREAT|O_RDWR|0666)) < 0)
- {
- perror("mkfifo");
- exit(1);
- }
- if((fd = open("my_fifo" , O_WRONLY)) < 0)
- {
- perror("open");
- exit(1);
- }
- if((write(fd,buf,strlen(buf)-1)) < 0)
- {
- perror("write");
- exit(1);
- }
- return 0;
-
- }
- #include<stdio.h>
- #include<stdlib.h>
- #include<fcntl.h>
- #include<sys/types.h>
- #include<sys/stat.h>
- int main(int argc,char *argv[])
- {
- int fd;
- char buf[20] = "";
- if((fd = open("my_fifo" , O_RDONLY)) < 0)
- {
- perror("open");
- exit(1);
- }
- if((read(fd,buf,20)) < 0)
- {
- perror("read");
- exit(1);
- }
- printf("%s" , buf);
- return 0;
-
- }
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Makefile- overpass:main.o
- g++ -g -o overpass main.o -L. -lhiredis -lpthread -lcurl -lrt -lcrypto -lidn -lssl
- main.o:main.cpp
- g++ -g -c main.cpp -o main.o
- clean:
- rm -f *.o overpass
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4.信号量- #include <stdio.h>
- #include <linux/sem.h>
- #define MAXNUMS 15
- int get_sem_val(int sid,int semnum)//取得当前信号量
- {
- return(semctl(sid,semnum,GETVAL,0));
- }
- int main(void)
- {
- int sem_id;
- int pid;
- int rc;
- struct sembuf sem_op;//信号集结构
- union semun sem_val;//信号量数值
-
-
- //建立信号量集,其中只有一个信号量
- sem_id=semget(IPC_PRIVATE,1,IPC_CREAT|0600);//IPC_PRIVATE私有,只有本用户使用,如果为正整数,则为公共的;1为信号集的数量;
- if (sem_id==-1){
- printf("create sem error!\n");
- exit(1);
- }
- printf("create %d sem success!\n",sem_id);
- //信号量初始化
- sem_val.val=1;
- rc=semctl(sem_id,0,SETVAL,sem_val);//设置信号量,0为第一个信号量,1为第二个信号量,...以此类推;SETVAL表示设置
- if (rc==-1){
- printf("initlize sem error!\n");
- exit(1);
- }
- //创建进程
- pid=fork();
- if (pid==-1){
- printf("fork error!\n");
- exit(1);
- }
- else if(pid==0){//一个子进程,消费者
- for (int i=0;i<MAXNUMS;i++){
- sem_op.sem_num=0;
- sem_op.sem_op=-1;
- sem_op.sem_flg=0;
- semop(sem_id,&sem_op,1);//操作信号量,每次-1
- printf("%d 消费者: %d\n",i,get_sem_val(sem_id,0));
- }
- }
- else{//父进程,生产者
- for (int i=0;i<MAXNUMS;i++){
- sem_op.sem_num=0;
- sem_op.sem_op=1;
- sem_op.sem_flg=0;
- semop(sem_id,&sem_op,1);//操作信号量,每次+1
- printf("%d 生产者: %d\n",i,get_sem_val(sem_id,0));
-
- }
- }
- exit(0);
- }
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Makefile- overpass:main.o
- g++ -g -o overpass main.o -L. -lhiredis -lpthread -lcurl -lrt -lcrypto -lidn -lssl
- main.o:main.cpp
- g++ -g -c main.cpp -o main.o
- clean:
- rm -f *.o overpass
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一般是用管道即可
更多参考:http://www.cnblogs.com/linshui91/archive/2010/09/29/1838770.html |
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