Pipe APIs

Data Structures
struct	k_pipe

Macros
#define	K_PIPE_DEFINE(name, pipe_buffer_size, pipe_align)
	Statically define and initialize a pipe.

Enumerations
enum	pipe_flags { PIPE_FLAG_OPEN = BIT(0) , PIPE_FLAG_RESET = BIT(1) }

Functions
void	k_pipe_init (struct k_pipe *pipe, uint8_t *buffer, size_t buffer_size)
	initialize a pipe
int	k_pipe_write (struct k_pipe *pipe, const uint8_t *data, size_t len, k_timeout_t timeout)
	Write data to a pipe.
int	k_pipe_read (struct k_pipe *pipe, uint8_t *data, size_t len, k_timeout_t timeout)
	Read data from a pipe This routine reads up to len bytes of data from pipe.
void	k_pipe_reset (struct k_pipe *pipe)
	Reset a pipe This routine resets the pipe, discarding any unread data and unblocking any threads waiting to write or read, causing the waiting threads to return with -ECANCELED.
void	k_pipe_close (struct k_pipe *pipe)
	Close a pipe.

Detailed Description

Macro Definition Documentation

K_PIPE_DEFINE

#define K_PIPE_DEFINE	(		name,
			pipe_buffer_size,
			pipe_align )

#include <zephyr/kernel.h>

Value:

        static unsigned char __noinit __aligned(pipe_align)             \
                _k_pipe_buf_##name[pipe_buffer_size];                   \
        STRUCT_SECTION_ITERABLE(k_pipe, name) =                         \
                Z_PIPE_INITIALIZER(name, _k_pipe_buf_##name, pipe_buffer_size)

Statically define and initialize a pipe.

The pipe can be accessed outside the module where it is defined using:

extern struct k_pipe <name>; 

Parameters

name	Name of the pipe.
pipe_buffer_size	Size of the pipe's ring buffer (in bytes).
pipe_align	Alignment of the pipe's ring buffer (power of 2).

Enumeration Type Documentation

pipe_flags

enum pipe_flags

#include <zephyr/kernel.h>

Enumerator
PIPE_FLAG_OPEN
PIPE_FLAG_RESET

Function Documentation

k_pipe_close()

void k_pipe_close

(

struct k_pipe *

pipe

)

#include <zephyr/kernel.h>

Close a pipe.

This routine closes a pipe. Any threads that were blocked on the pipe will be unblocked and receive an error code.

Parameters

pipe	Address of the pipe.

k_pipe_init()

void k_pipe_init	(	struct k_pipe *	pipe,
		uint8_t *	buffer,
		size_t	buffer_size )

#include <zephyr/kernel.h>

initialize a pipe

This routine initializes a pipe object, prior to its first use.

Parameters

pipe	Address of the pipe.
buffer	Address of the pipe's buffer.
buffer_size	Size of the pipe's buffer.

k_pipe_read()

int k_pipe_read	(	struct k_pipe *	pipe,
		uint8_t *	data,
		size_t	len,
		k_timeout_t	timeout )

#include <zephyr/kernel.h>

Read data from a pipe This routine reads up to len bytes of data from pipe.

If the pipe is empty, the routine will block until the data can be read or the timeout expires.

Parameters

pipe	Address of the pipe.
data	Address to place the data read from pipe.
len	Requested number of bytes to read.
timeout	Waiting period to wait for the data to be read.

Return values

number	of bytes read on success
-EAGAIN	if no data could be read before the timeout expired
-ECANCELED	if the read was interrupted by k_pipe_reset(..)
-EPIPE	if the pipe was closed

k_pipe_reset()

void k_pipe_reset

(

struct k_pipe *

pipe

)

#include <zephyr/kernel.h>

Reset a pipe This routine resets the pipe, discarding any unread data and unblocking any threads waiting to write or read, causing the waiting threads to return with -ECANCELED.

Calling k_pipe_read(..) or k_pipe_write(..) when the pipe is resetting but not yet reset will return -ECANCELED. The pipe is left open after a reset and can be used as normal.

Parameters

pipe	Address of the pipe.

k_pipe_write()

int k_pipe_write	(	struct k_pipe *	pipe,
		const uint8_t *	data,
		size_t	len,
		k_timeout_t	timeout )

#include <zephyr/kernel.h>

Write data to a pipe.

This routine writes up to len bytes of data to pipe. If the pipe is full, the routine will block until the data can be written or the timeout expires.

Parameters

pipe	Address of the pipe.
data	Address of data to write.
len	Size of data (in bytes).
timeout	Waiting period to wait for the data to be written.

Return values

number	of bytes written on success
-EAGAIN	if no data could be written before the timeout expired
-ECANCELED	if the write was interrupted by k_pipe_reset(..)
-EPIPE	if the pipe was closed