Re: When reading from a serialport read returns a Bad Address/EFAULT error

[Paul Pluzhnikov]

tlann@technoeclectic.com writes:

> When I'm trying to read from a serial port configured as 9600baud 081 I
> get a EFAULT/Bad address error.

Your problem has nothing whatsoever to do with serial port.

> unsigned char* SerialPort::rcvChar(int bytestoread)
> {
>       unsigned char* temp;
>       if (read(m_iFd, temp, bytestoread) < 0)

Reading butes into memory, pointed at by *uninitialized* pointer,
is a bad idea (TM).

The obvious correction is something like this:

    unsigned char* SerialPort::rcvChar(int bytestoread)
    {
        unsigned char temp[bytestoread]; // note: gcc extension
        if (read(m_iFd, temp, bytestoread) < 0)

and this will cure the EFAULT, but will not produce correct results
upon return. Why that is so is left as an exercise for the reader.

Cheers,
-- 
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