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TTY streams are used to represent serial connections that are fully "streamable" objects using C++ stream classes and friends.
The first application relevant serial I/O class is the TTYStream class. TTYStream offers a linearly buffered "streaming" I/O session with the serial device. Furthermore, traditional C++ "stream" operators (<< and >>) may be used with the serial device. A more "true" to ANSI C++ library format "ttystream" is also available, and this supports an "open" method in which one can pass initial serial device parameters immediately following the device name in a single string, as in "/dev/tty3a:9600,7,e,1", as an example.
The TTYSession aggragates a TTYStream and a Common C++ Thread which is assumed to be the execution context that will be used to perform actual I/O operations. This class is very anagolous to TCPSession.
char * gbuf | gbuf |
[protected]
char * pbuf | pbuf |
[protected]
timeout_t timeout | timeout |
[protected]
TTYStream ()
| TTYStream |
[protected]
This constructor is used to derive "ttystream", a more C++ style version of the TTYStream class.
void Allocate (void)
| Allocate |
[protected]
Used to allocate the buffer space needed for iostream operations. This is based on MAX_INPUT.
void endStream (void)
| endStream |
[protected]
Used to terminate the buffer space and clean up the tty connection. This function is called by the destructor.
int underflow (void)
| underflow |
[protected]
This streambuf method is used to load the input buffer through the established tty serial port.
Returns: char from get buffer, EOF also possible.
int uflow (void)
| uflow |
[protected]
This streambuf method is used for doing unbuffered reads through the establish tty serial port when in interactive mode. Also this method will handle proper use of buffers if not in interative mode.
Returns: char from tty serial port, EOF also possible.
int overflow (int ch)
| overflow |
[protected]
This streambuf method is used to write the output buffer through the established tty port.
Parameters:
char | to push through. |
Returns: char pushed through.
TTYStream (const char *filename)
| TTYStream |
Create and ipen a tty serial port.
Parameters:
char | name of device to open. |
~TTYStream ()
| ~TTYStream |
[virtual]
End the tty stream and cleanup.
inline void setTimeout (timeout_t to)
| setTimeout |
Set the timeout control.
Parameters:
timeout | to use. |
void Interactive (bool flag)
| Interactive |
Set tty mode to buffered or "interactive". When interactive, all streamed I/O is directly sent to the serial port immediately.
Parameters:
bool | set to true to make interactive. |
int sync (void)
| sync |
Flushes the stream input and out buffers, writes pending output.
Returns: 0 on success.
bool isPending (siopend_t pend, timeout_t timeout = TIMEOUT_INF)
| isPending |
Get the status of pending operations. This can be used to examine if input or output is waiting, or if an error has occured on the serial device. If read buffer contains data then input is ready and if write buffer contains data it is first flushed then checked.
Parameters:
ready | check to perform. |
timeout | in milliseconds. |
Returns: true if ready, false if timeout.
Reimplemented from Serial.