xtos_bci_read_samples

Performs one device read directly into a float buffer and returns the byte count divided by sizeof(float).

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Declaration

#include <xtos/bci.h>

ssize_t xtos_bci_read_samples(xtos_bci_session_t *session,
                             float *buffer,
                             size_t num_samples);

Parameters

Parameter	Type	Description
session	xtos_bci_session_t *	Non-NULL session handle.
buffer	float *	Non-NULL caller-owned buffer holding at least num_samples floats.
num_samples	size_t	Requested scalar float count, greater than zero; it is not automatically a frame count.

Return value

Returns a nonnegative count and permits short reads; returns -1 on failure.

Errors

errno	Condition
EINVAL	session or buffer is NULL, or num_samples is zero.
EAGAIN/EINTR	A nonblocking setup or signal interruption can make the underlying read return these errno values.
system errno	Other read failures preserve the underlying errno.

Notes

The public implementation does not check multiplication overflow, frame alignment, or timestamps; read may block by default and callers must handle short reads.
The public driver writes int32 nanovolt bytes while this implementation reads them directly into float* without int32→float or nV→µV conversion; do not interpret it as floating-point EEG.
The caller allocates and frees buffer; the function returns no device timestamp, sequence, quality flag, or reliable frame boundary.

Example

Source

This reference describes headers and implementation at OpenXTOS commit dd313955ad57542bcd2af8827157d1bbd0cf5e83.