虚拟串口基础读写例子，记录备忘
环境：win10 + mingw64

操作虚拟串口和物理串口的区别只是串口名称不同，需要用个奇怪的写法，比如虚拟串口号为21：

char portName[] = "\\.\COM21"

物理串口就可以直接写串口号，比如物理串口6：

char portName[] = "COM6"

不区分大小写，下面是一个示例程序：

#include <stdio.h>
#include <windows.h>

int main(int argc, char *argv[]) {
    HANDLE hSerial;
    DCB dcbSerialParams = {0};
    COMMTIMEOUTS timeouts = {0};
    //char portName[] = "COM6";       // 物理串口的设备路径，根据实际情况修改
    char portName[] = "\\.\COM21"; // 虚拟串口的设备路径，根据实际情况修改
    char data[] = "Hello, Serial!"; // 待发送的数据

    // 打开串口
    hSerial = CreateFile(portName,
                         GENERIC_READ | GENERIC_WRITE,
                         0,
                         NULL,
                         OPEN_EXISTING,
                         FILE_ATTRIBUTE_NORMAL,
                         NULL);
    if (hSerial == INVALID_HANDLE_VALUE)
    {
        printf("Failed to open serial port
");
        return 1;
    }

    // 配置串口参数
    dcbSerialParams.DCBlength = sizeof(dcbSerialParams);
    if (!GetCommState(hSerial, &dcbSerialParams))
    {
        printf("Failed to get current serial parameters
");
        CloseHandle(hSerial);
        return 1;
    }
    dcbSerialParams.BaudRate = CBR_115200; // 波特率
    dcbSerialParams.ByteSize = 8; // 数据位数
    dcbSerialParams.StopBits = ONESTOPBIT; // 停止位
    dcbSerialParams.Parity = NOPARITY; // 校验位
    if (!SetCommState(hSerial, &dcbSerialParams))
    {
        printf("Failed to set serial parameters
");
        CloseHandle(hSerial);
        return 1;
    }

    // 配置读取超时
    timeouts.ReadIntervalTimeout = 50;
    timeouts.ReadTotalTimeoutConstant = 50;
    timeouts.ReadTotalTimeoutMultiplier = 10;
    timeouts.WriteTotalTimeoutConstant = 50;
    timeouts.WriteTotalTimeoutMultiplier = 10;
    if (!SetCommTimeouts(hSerial, &timeouts))
    {
        printf("Failed to set serial timeouts
");
        CloseHandle(hSerial);
        return 1;
    }

    // 发送数据
    DWORD bytesWritten;
    if (!WriteFile(hSerial, data, sizeof(data), &bytesWritten, NULL))
    {
        printf("Failed to write to serial port
");
        CloseHandle(hSerial);
        return 1;
    }
    printf("Sent %d bytes
", bytesWritten);

    // 读取数据
    DWORD bytesRead;
    char buffer[256];
    if (!ReadFile(hSerial, buffer, sizeof(buffer), &bytesRead, NULL))
    {
        printf("Failed to read from serial port
");
        CloseHandle(hSerial);
        return 1;
    }
    printf("Received %d bytes: %s
", bytesRead, buffer);

    // 关闭串口
    CloseHandle(hSerial);

    return 0;
}

测试可以成功收发，绑定的对应串口收到数据：