ReadFile() 尝试从 USB 端口读取数据时出现错误 998

Question

我正在尝试使用我自己的应用程序通过 USB 将数据从 STM32 探索板发送到主机 PC。我设法将数据发送到 STM。我为此使用了 WriteFile。为了读取数据，我调用函数 readSerialPort()，它调用函数 ReadFile().

In main.c readSerialPort() 在 while 循环中被调用。每当我向 PC 发送一些测试数据（4 个随机字节）时，我可以看到 status.cbInQue 变大了 4，但 ReadFile 没有 return TRUE，表明它已完成将数据放入缓冲区指针导致 receivedData().

当我做GetLastErrror()时，它return的错误代码是998。这意味着ERROR_NOACCESS，通常这意味着分配的数组与 buf_size 不同，但它是。那么是什么原因导致此错误并导致无法通过 USB 从 STM 接收数据？

（我对在 Whosebug 上提问很陌生，所以如果我需要改进我提出这个问题的方式，请告诉我）

main.c

char* receivedData[31];     
uint32_t id = 0;        
while(1) {  
if (readSerialPort(*receivedData, 31)) {
    printf("%d - %s\n", id, receivedData);
    id++;       
} else {            
    printf("error %u\n", GetLastError());       
}

comm.c

#include "comm.h"

HANDLE handler;
uint8_t connected;

COMSTAT status;
DWORD errors;

int connectSerial(char* portName) {
    connected = 0;
    handler = CreateFileA(portName,
                                GENERIC_READ | GENERIC_WRITE,
                                0,
                                0,
                                OPEN_EXISTING,
                                FILE_ATTRIBUTE_NORMAL,
                                0);
    if (handler == INVALID_HANDLE_VALUE) {
        if (GetLastError() == ERROR_FILE_NOT_FOUND) {
            printf("ERROR: Handle was not attached. Reason: %s not available\n", portName);
        } else {
            printf("ERROR!!!");
        }
    } else {
        DCB dcbSerialParameters = { 0 };

        if (!GetCommState(handler, &dcbSerialParameters)) {
            printf("failed to get current serial parameters");
        } else {
            connected = 1;
            PurgeComm(handler, PURGE_RXCLEAR | PURGE_TXCLEAR);
            //  Sleep(2000);
        }
    }
}

void disconnectSerial() {
    if (connected) {
        connected = 0;
        CloseHandle(handler);
    }
}

uint8_t readSerialPort(char* buffer, unsigned int buf_size) {
    DWORD bytesRead;
    unsigned int toRead;

    ClearCommError(handler, &errors, &status);

    if (status.cbInQue > 0) {
        if (status.cbInQue > buf_size) 
            toRead = buf_size;
        else
            toRead = status.cbInQue;
    }

    if (ReadFile(handler, buffer, toRead, &bytesRead, NULL))
        return bytesRead;
    return 0;
}

uint8_t writeSerialPort(char* buffer, unsigned int buf_size) {
    DWORD bytesSend;

    if (!WriteFile(handler, (void*)buffer, buf_size, &bytesSend, 0)) {
        ClearCommError(handler, &errors, &status);
        return 0;
    }
    else return 1;
}

Answer 1

Johnny 的第一条评论解决了我的问题：

char* receivedData[31]; is an array of uninitialized pointers. Did you mean char receivedData[31];? And then call: if (readSerialPort(receivedData, 31)) {

ReadFile() 尝试从 USB 端口读取数据时出现错误 998

ReadFile() gives error 998 when trying to read data from USB port

c

usb

serial-port

stm32

readfile