Modbus 设备（利用 slave 模拟）

Modbus 采集程序

client.c

#include "client.h"modbus_t *ctx;
key_t key_shm, key_msg;
int shmid, msgid;
struct shm *shm0;
struct msgbuf msg0;void *collector(void *arg) {struct shm *p = (struct shm *)arg;while (1){sleep(1);if (modbus_read_registers(ctx, 0, 4, p->buf) < 0) {perror("Failed to modbus_read_registers");return NULL;}printf("LIGHT SENSOR: %d\n", p->buf[0]);printf("ACCELERATION SENSOR-X: %d\n", p->buf[1]);printf("ACCELERATION SENSOR-Y: %d\n", p->buf[2]);printf("ACCELERATION SENSOR-Z: %d\n\n", p->buf[3]);}pthread_exit(0);
}void *control(void *arg) {while (1){msgrcv(msgid, &msg0, sizeof(msg0)-sizeof(long), 250, 0);printf("LED: %c\n", msg0.ctl[0]);printf("BUZZER: %c\n\n", msg0.ctl[1]);modbus_write_bit(ctx, msg0.ctl[0]-48, msg0.ctl[1]-48);}pthread_exit(0);
}int main(int argc, char const *argv[])
{   if (argc != 3) {printf("Please input %s <ip> <port>. \n", argv[0]);return -1;}init_modbus(&ctx, argv[1], atoi(argv[2]));shm0 = init_shared_memory(&key_shm, &shmid);printf("The key(shm): %#x\n", key_shm);printf("The shmid: %d\n", shmid);init_msg_queue(&key_msg, &msgid);msg0.mtype = 250;printf("The key(msg): %#x\n", key_msg);printf("The msgid: %d\n", msgid);pthread_t tid1, tid2;if (pthread_create(&tid1, NULL, collector, shm0)) {perror("Failed to create a thread named collector");return -1;}if (pthread_create(&tid2, NULL, control, msg0.ctl)) {perror("Failed to create a thread named input");return -1;}pthread_join(tid1, NULL);pthread_join(tid2, NULL);// shmdt(p);// shmctl(shmid, IPC_RMID, NULL);// msgctl(msgid, IPC_RMID, NULL);modbus_close(ctx);modbus_free(ctx);return 0;
}

client.h

#ifndef __CLIENT_H_
#define __CLIENT_H_#include <stdio.h>
#include <modbus.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/msg.h>#define SHM_SIZE 64struct shm {uint16_t buf[4];// int flag;
};struct msgbuf {long mtype;    		/* message type, must be > 0 */uint8_t ctl[2]; 	/* message data */
};int init_modbus(modbus_t **, const char *, int);
struct shm *init_shared_memory(key_t *, int *);
int init_msg_queue(key_t *, int *);#endif

func.c

#include "client.h"int init_modbus(modbus_t **ctx, const char *ip, int port) {*ctx = modbus_new_tcp(ip, port);if (*ctx == NULL) {perror("Failed to modbus_new_tcp");return -1;}if (modbus_set_slave(*ctx, 1) < 0) {perror("Failed to modbus_set_slave");return -2;}if (modbus_connect(*ctx) < 0) {perror("Failed to modbus_connect");return -3;}return 0;
}struct shm *init_shared_memory(key_t *key, int *shmid) {*key = ftok("./client.c", 'v');        // ftok(任意文件名/路径名, 任意字符);if (key < 0) {perror("Failed to ftok");return NULL;}*shmid = shmget(*key, SHM_SIZE, IPC_CREAT | IPC_EXCL | 0666);if (*shmid < 0) {if (errno == EEXIST)*shmid = shmget(*key, SHM_SIZE, 0666);else {perror("Failed to shmget");return NULL;}}struct shm *p = shmat(*shmid, NULL, 0);     // 0 表示可读可写, 若只读则 SHM_RDONLYif (p == (void *)-1) {				   		// if (*p == -1) 也可以perror("Failed to shmat");return NULL;}return p;
}int init_msg_queue(key_t *key, int *msgid) {*key = ftok("./client.h", 'v');if (*key < 0){perror("Failed to ftok");return -4;}*msgid = msgget(*key, IPC_CREAT | IPC_EXCL | 0666);if (