在H3開發板上跑linux，想用他讀取串口資訊。比如用串口工具發abcde
但是讀出來的內容第一次讀第一位的a丟失，第二次讀全部出來了，第三次又沒有a，第4次又讀出來了，一直這樣回圈。
求告知是什么問題？
代碼如下：
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <iostream>
using namespace std;
int set_interface_attribs(int fd, int speed)
{
struct termios tty;
if (tcgetattr(fd, &tty) < 0) {
printf("Error from tcgetattr: %s\n", strerror(errno));
return -1;
}
cfsetospeed(&tty, (speed_t)speed);
cfsetispeed(&tty, (speed_t)speed);
tty.c_cflag |= (CLOCAL | CREAD); /* ignore modem controls */
tty.c_cflag &= ~CSIZE;
tty.c_cflag |= CS8; /* 8-bit characters */
tty.c_cflag &= ~PARENB; /* no parity bit */
tty.c_cflag &= ~CSTOPB; /* only need 1 stop bit */
tty.c_cflag &= ~CRTSCTS; /* no hardware flowcontrol */
/* setup for non-canonical mode */
tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
tty.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
tty.c_oflag &= ~OPOST;
/* fetch bytes as they become available */
tty.c_cc[VMIN] = 1;
tty.c_cc[VTIME] = 1;
if (tcsetattr(fd, TCSANOW, &tty) != 0) {
printf("Error from tcsetattr: %s\n", strerror(errno));
return -1;
}
return 0;
}
void set_mincount(int fd, int mcount)
{
struct termios tty;
if (tcgetattr(fd, &tty) < 0) {
printf("Error tcgetattr: %s\n", strerror(errno));
return;
}
tty.c_cc[VMIN] = mcount ? 1 : 0;
tty.c_cc[VTIME] = 5; /* half second timer */
if (tcsetattr(fd, TCSANOW, &tty) < 0)
printf("Error tcsetattr: %s\n", strerror(errno));
}
int main()
{
char *portname = "/dev/ttyS0";
int fd;
int wlen;
fd = open(portname, O_RDWR | O_NOCTTY | O_SYNC);
if (fd < 0) {
printf("Error opening %s: %s\n", portname, strerror(errno));
return -1;
}
/*baudrate 9600, 8 bits, no parity, 1 stop bit */
//set_mincount(fd, 0); /* set to pure timed read */
set_interface_attribs(fd, B115200);
char buf[64];
int rdlen = 0;
/* simple noncanonical input */
do {
memset(buf,0,sizeof(buf));
rdlen = read(fd, buf, sizeof(buf));
if (rdlen > 0) {
cout<<"rdlen:"<<rdlen<<" buf:"<<buf<<endl;
} else if (rdlen < 0) {
printf("Error from read: %d: %s\n", rdlen, strerror(errno));
}
sleep(0);
/* reeat read to get full message */
} while (1);
}
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標籤：應用程序開發區
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