stream_poke_single :: Quanser C Functions

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stream_poke_single

Writes a single-precision (32-bit) floating-point number to the stream buffer.

Description

This function writes a single-precision (32-bit) floating-point number to the stream buffer. It attempts to store the floating-point number in the stream buffer. If there is enough room available in the stream buffer then it stores the data in the buffer and returns immediately. However, the stream pointer is not advanced, so the data is not written to the actual communication channel. The data will only be written to the underlying communication channel if stream_poke_end is called. If an error occurs, then it returns a negative error code. If the connection is closed it is considered an error condition.

If the stream has been configured to swap bytes using stream_set_swap_bytes or stream_set_byte_order then this function will swap the order of the bytes within the single floating-point number when they are poked.

If stream_listen or stream_connect was called with the non-blocking flag set to false (0), then this function may block attempting to flush the stream buffer (to write out data previously sent and still waiting in the stream buffer). Once the single-precision floating-point number is poked into the buffer then 1 is returned. If an error occurs then the error code is returned and the stream should be closed.

If stream_listen or stream_connect was called with the non-blocking flag set to true (1), then this function does not block. It returns 1 if the data is poked successfully. If the single-precision floating-point number could not be poked without blocking, then -QERR_WOULD_BLOCK is returned. If an error occurs then the error code is returned and the stream should be closed.

This function does not support two threads poking or flushing data at the same time. However, data may be poked or the stream flushed by another thread at the same time as data is being received.

The BSD socket API has no equivalent to this function.

Prototype

t_int
stream_poke_single(t_stream stream, t_stream_poke_state * state, t_single value);

Parameters

t_stream stream

A client stream established using stream_connect or stream_accept.

t_stream_poke_state * state

The poke state initialized using stream_poke_begin.

t_single value

The value to be poked.

Return value

Returns 1 on success. If an error occurs then a negative error code is returned.

Error codes

This function does not return any error code.

Requirements

Include Files	Libraries
quanser_stream.h	quanser_communications.lib;quanser_runtime.lib;quanser_common.lib