C / C++ / MFC

Jochen Arndt wrote:

CREAD is probably set but what about CLOCAL?

if(tcgetattr(hComPort, &config) < 0)
    {
        cout << "configuration of the serial interface not found\n" << endl;
        cout << "Hit <S> to Stop .." << endl;
        cin >> c;
        c = (char)toupper(c);
        if (c == 'S') Error = true;
    }
    memset(&config, 0, sizeof(config));

config.c_cflag = CS8 | CREAD | CLOCAL; // 8N1, enable receiver, ignore ctrl lines
    
    if(cfsetispeed(&config, B9600) < 0 || cfsetospeed(&config, B9600) < 0)
    {
        cout << "Baud Rate did not set correctly\n" << endl;
        cout << "Hit <S> to Stop .." << endl;
        cin >> c;
        c = (char)toupper(c);
        if (c == 'S') Error = true;
    }

read(hComPort, &c, 1);
if ((c >= 0x20) && (c <= 0x7E)) data[cnt++] = c;

Quote:

Return Value
On success, the number of bytes read is returned (zero indicates end of file), and the file position is advanced by this number. It is not an error if this number is smaller than the number of bytes requested; this may happen for example because fewer bytes are actually available right now (maybe because we were close to end-of-file, or because we are reading from a pipe, or from a terminal), or because read() was interrupted by a signal. On error, -1 is returned, and errno is set appropriately. In this case it is left unspecified whether the file position (if any) changes.

int received = read(hComPort, &c, 1);
if (received == 1 && c >= 0x20 && c <= 0x7E) 
    data[cnt++] = c;
else if (received < 0)
    // handle error here

void ComPort::ReadComPortDataMsg(char *data)
{
    int cnt = 0;
    int received;
    char c;

    data[0] = 0x00;
    do
    {
        received = read(hComPort, &c, 1);
        if ((received == 1) && (c >= 0x20) && (c <= 0x7E))
        {
            data[cnt++] = c;
        }
        else if (received < 0)
        {
            
        }
    } while ((c != dlim) && (cnt < 255));
    data[cnt++] = '\0';
}

struct termios

global errno variable

man errno

CPallini wrote:

IDEs are for sissies.

(And yes, I'm old enough to have actually written programs that way. )

char* x = (char*)calloc(sizeof(char),150);
char** p = &x;
free(x);
x = NULL;
printf("%p\n", *p); // here *p is NULL

CPallini wrote:

*p is NULL