FIFO通信 htonl 和memcpy的用法

void Fifowrite()                                       //Fifo通信{        int real_wnum = 0;          int fifo_fd = open(OSD_FIFO,O_WRONLY,0);          printf("fifo: %d\n", fifo_fd);          if(fifo_fd)          {            real_wnum = write(fifo_fd,&osd_t,sizeof(textOSD_t));            if(real_wnum==-1)                printf("write to fifo error; try later real_wnum=%d\n",real_wnum);            else                 printf("real write num is %d\n",real_wnum);            //close            close(fifo_fd);         }    }int setfifoimage( unsigned char Fifo_ID,unsigned char imgID,int imgvalue){        wta_fifocmd_t imagefifo;    imagefifo.Cmdhead=0x01;         imagefifo.Cmd_ver=0x01;    imagefifo.Cmd_ID=Fifo_ID;        imagefifo.Cmd_Para[0]=imgID;    imagefifo.Cmd_Para[1]=imgvalue;    imagefifo.Cmd_check=0x00;    int real_wnum = 0;    int fifo_fd = open(IMAGE_FIFO,O_WRONLY,0);    printf("fifo: %d\n", fifo_fd);    if(fifo_fd)      {         real_wnum = write(fifo_fd,&imagefifo,sizeof(wta_fifocmd_t));         if(real_wnum==-1)             printf("write to fifo error; try later real_wnum=%d\n",real_wnum);         else              printf("real write num is %d\n",real_wnum);             printf("Cmd_Para[0]:%d\n",imagefifo.Cmd_Para[0]);             printf("Cmd_Para[1]:%d\n",imagefifo.Cmd_Para[1]);       close(fifo_fd);      }           }simg_t.exposure_set.shutter_time_min=gatoi(pszTmp);            nTmp = htonl(simg_t.exposure_set.shutter_time_min);             //htonl的用法。本函数将一个32位数从主机字节顺序转换成网络字节顺序            memcpy(shutterTmp, &nTmp, 4);                 nTmp = htonl(simg_t.exposure_set.shutter_time_max);            memcpy(shutterTmp+4, &nTmp, 4);            nTmp = htonl(simg_t.exposure_set.slow_shutter_enable);            memcpy(shutterTmp+8, &nTmp, 4);            shutterfifo(WTA_IMAGE_QULITY_SET, WTA_AE_SHUTTER_RANG_SET, shutterTmp,CPCOUNT);

http://www.cnblogs.com/qingjoin/archive/2011/12/06/2278173.html