共享内存

进程A：

 1 //processA.c文件  2 #include <stdlib.h>  3 #include <stdio.h>  4 #include <sys/shm.h>  5 #include <unistd.h>  6 #include <string.h>  7 #include <sys/types.h>  8 #include <sys/ipc.h>  9 #include <errno.h> 10 #include <pthread.h> 11   12 #define BUF_SIZE 4096 13   14 int main() 15 { 16     void *shm_addr = NULL; 17     char buffer[BUF_SIZE]; 18     pthread_mutex_t * sharedLock; 19     pthread_mutexattr_t ma; 20   21     int shmid; 22     // 使用约定的键值创建共享内存 23     shmid = shmget((key_t) 1234,  BUF_SIZE, 0666 | IPC_CREAT); 24     printf(shmid : %u\n, shmid); 25     if (shmid < 0) 26     { 27         perror(shmget error!); 28         exit(1); 29     } 30   31     // 将共享内存附加到本进程 32     shm_addr = shmat(shmid, NULL, 0); 33     if (shm_addr == (void *) -1) 34     { 35         perror(shmat error!); 36         exit(1); 37     } 38   39     sharedLock = (pthread_mutex_t *)shm_addr; 40   41     pthread_mutexattr_init(&ma); 42     pthread_mutexattr_setpshared(&ma, PTHREAD_PROCESS_SHARED); 43     pthread_mutexattr_setrobust(&ma, PTHREAD_MUTEX_ROBUST); 44     pthread_mutex_init(sharedLock,&ma); 45   46     // 写入数据 47     while(1){ 48         pthread_mutex_lock(sharedLock); 49         bzero(buffer, BUF_SIZE); 50         sprintf(buffer, Hello, My PID is %u\n, (unsigned int) getpid()); 51         printf(send data: %s\n, buffer); 52         memcpy(((pthread_mutex_t *)shm_addr)+1, buffer, strlen(buffer)); 53         pthread_mutex_unlock(sharedLock); 54     } 55   56     sleep(5); 57   58     // 分离 59     if (shmdt(shm_addr) == -1) 60     { 61         printf(shmdt error!\n); 62         exit(1); 63     } 64 }

View Code   进程B：

 1 //processB.c文件  2 #include <stdio.h>  3 #include <stdlib.h>  4 #include <sys/shm.h>  5 #include <sys/ipc.h>  6 #include <sys/types.h>  7 #include <unistd.h>  8 #include <string.h>  9 #include <errno.h> 10 #include <pthread.h> 11   12 #define BUF_SIZE 4096 13   14 int main() 15 { 16     void *shm_addr = NULL; 17     pthread_mutex_t * sharedLock; 18     char tmp[BUF_SIZE]; 19   20     int shmid; 21     // 使用约定的键值打开共享内存 22     shmid = shmget((key_t) 1234, BUF_SIZE, IPC_CREAT); 23     printf(shmid : %u\n, shmid); 24     if (shmid == -1) 25     { 26         perror(shmget error!); 27         exit(1); 28     } 29   30     // 将共享内存附加到本进程 31     shm_addr = shmat(shmid, NULL, 0); 32     if (shm_addr == (void *) -1) 33     { 34         perror(shmat error!); 35         exit(1); 36     } 37   38     sharedLock = (pthread_mutex_t *)shm_addr; 39   40     // 读取数据 41     while(1){ 42         pthread_mutex_lock(sharedLock); 43         bzero(tmp, BUF_SIZE); 44         memcpy(tmp, ((pthread_mutex_t *)shm_addr)+1, 50); 45         printf(read from shared memory: %s\n, tmp); 46         pthread_mutex_unlock(sharedLock); 47     } 48   49     sleep(5); 50   51     // 分离 52     if (shmdt(shm_addr) == -1) 53     { 54         printf(shmdt error!\n); 55         exit(1); 56     } 57   58     // 删除共享内存 59     if (shmctl(shmid, IPC_RMID, 0) == -1) 60     { 61         printf(shmctl error!\n); 62         exit(1); 63     } 64 }

View Code