我正在进行串行COM端口ANSI Char读取项目。我可以处理发送数据,但我无法处理收到它。任何帮助都是适当的。
这是读函数:
BOOL ReadString(char *outstring)
{
int *length;
*length = sizeof(int);
BYTE data;
BYTE dataout[8192]={0};
int index = 0;
while(ReadByte(data)== TRUE)
{
dataout[index++] = data;
}
memcpy(outstring, dataout, index);
*length = index;
return TRUE;
}
Main.cpp是:
int main(void)
{
// Configs
hPort = ConfigureSerialPort("COM1");
if(hPort == NULL)
{
printf("Com port configuration failed\n");
return -1;
}
char* cPTR;
for(;;)
{
ReadString(cPTR);
if(cPTR!=NULL) cout << "Scanned Data: " << cPTR << endl;
else cout << "No data recieved." << endl;
}
ClosePort();
return 0;
}
答案 0 :(得分:1)
有多个错误:使用C-strings而不是std :: string,没有绑定检查,e.t.c。:
BOOL ReadString(char *outstring)
{
int *length; // !!!! length is not initialized, it may point to any address
*length = sizeof(int);
BYTE data;
BYTE dataout[8192]={0};
int index = 0;
while(ReadByte(data)== TRUE) // !!!! No bound check. What if index will become more than 8192?
{
dataout[index++] = data;
}
memcpy(outstring, dataout, index);
*length = index; // Hmm, length is not static it is automatic variable and will not keep the index between the calls
return TRUE;
}
主要:
int main(void)
{
// Configs
hPort = ConfigureSerialPort("COM1");
if(hPort == NULL)
{
printf("Com port configuration failed\n");
return -1;
}
char* cPTR; // !!!! Not initialized, points to any place in memory
for(;;)
{
ReadString(cPTR); // !!!! cPTR not allocated, you pass the pointer to somwhere
if(cPTR!=NULL)
cout << "Scanned Data: " << cPTR << endl;
else
cout << "No data recieved." << endl;
}
ClosePort();
return 0;
}
我的读取字符串函数的建议:
void ReadString(
std::string& result,
std::size_t& size)
{
result.clear(); // If you need to keep track - don't clear
BYTE byteIn;
while (ReadByte(byteIn))
{
result.append(byteIn); // Maybe static_cast<char>(byteIn) required for BYTE to char
size++;
}
}
现在我们可以将main重写为:
std::string buffer;
std::size_t length = 0;
while (true)
{
ReadString(buffer, length);
if(buffer.size())
cout << "Scanned Data: " << buffer << endl;
else
cout << "No data recieved." << endl;
// Some condition to break the cycle after 1Mb
if (length > 1024 * 1024)
break;
}