Represents a single GPIO line. More...

#include <gpiod.hpp>

Public Types
enum	: int { DIRECTION_INPUT = 1, DIRECTION_OUTPUT }
	Possible direction settings. More...

enum	: int { ACTIVE_LOW = 1, ACTIVE_HIGH }
	Possible active state settings. More...

enum	: int { BIAS_AS_IS = 1, BIAS_DISABLE, BIAS_PULL_UP, BIAS_PULL_DOWN }
	Possible bias settings. More...

Public Member Functions
GPIOD_API	line (void)
	Default constructor. More...

GPIOD_API	line (const line &other)=default
	Copy constructor. More...

GPIOD_API	line (line &&other)=default
	Move constructor. More...

GPIOD_API line &	operator= (const line &other)=default
	Assignment operator. More...

GPIOD_API line &	operator= (line &&other)=default
	Move assignment operator. More...

GPIOD_API	~line (void)=default
	Destructor.

GPIOD_API unsigned int	offset (void) const
	Get the offset of this line. More...

GPIOD_API ::std::string	name (void) const
	Get the name of this line (if any). More...

GPIOD_API ::std::string	consumer (void) const
	Get the consumer of this line (if any). More...

GPIOD_API int	direction (void) const
	Get current direction of this line. More...

GPIOD_API int	active_state (void) const
	Get current active state of this line. More...

GPIOD_API int	bias (void) const
	Get current bias of this line. More...

GPIOD_API bool	is_used (void) const
	Check if this line is used by the kernel or other user space process. More...

GPIOD_API bool	is_open_drain (void) const
	Check if this line represents an open-drain GPIO. More...

GPIOD_API bool	is_open_source (void) const
	Check if this line represents an open-source GPIO. More...

GPIOD_API void	request (const line_request &config, int default_val=0) const
	Request this line. More...

GPIOD_API void	release (void) const
	Release the line if it was previously requested.

GPIOD_API bool	is_requested (void) const
	Check if this user has ownership of this line. More...

GPIOD_API int	get_value (void) const
	Read the line value. More...

GPIOD_API void	set_value (int val) const
	Set the value of this line. More...

GPIOD_API void	set_config (int direction, ::std::bitset< 32 > flags, int value=0) const
	Set configuration of this line. More...

GPIOD_API void	set_flags (::std::bitset< 32 > flags) const
	Set configuration flags of this line. More...

GPIOD_API void	set_direction_input () const
	Change the direction this line to input.

GPIOD_API void	set_direction_output (int value=0) const
	Change the direction this lines to output. More...

GPIOD_API bool	event_wait (const ::std::chrono::nanoseconds &timeout) const
	Wait for an event on this line. More...

GPIOD_API line_event	event_read (void) const
	Read a line event. More...

GPIOD_API ::std::vector< line_event >	event_read_multiple (void) const
	Read multiple line events. More...

GPIOD_API int	event_get_fd (void) const
	Get the event file descriptor associated with this line. More...

GPIOD_API const chip &	get_chip (void) const
	Get the reference to the parent chip. More...

GPIOD_API void	update (void) const
	Re-read the line info from the kernel.

GPIOD_API void	reset (void)
	Reset the state of this object. More...

GPIOD_API bool	operator== (const line &rhs) const noexcept
	Check if two line objects reference the same GPIO line. More...

GPIOD_API bool	operator!= (const line &rhs) const noexcept
	Check if two line objects reference different GPIO lines. More...

GPIOD_API	operator bool (void) const noexcept
	Check if this object holds a reference to any GPIO line. More...

GPIOD_API bool	operator! (void) const noexcept
	Check if this object doesn't reference any GPIO line. More...

Detailed Description

Represents a single GPIO line.

Internally this class holds a raw pointer to a GPIO line descriptor and a reference to the parent chip. All line resources are freed when the last reference to the parent chip is dropped.

Definition at line 262 of file gpiod.hpp.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum : int

Possible direction settings.

Enumerator
DIRECTION_INPUT	Line's direction setting is input.
DIRECTION_OUTPUT	Line's direction setting is output.

Definition at line 490 of file gpiod.hpp.

◆ anonymous enum

anonymous enum : int

Possible active state settings.

Enumerator
ACTIVE_LOW	Line's active state is low.
ACTIVE_HIGH	Line's active state is high.

Definition at line 500 of file gpiod.hpp.

◆ anonymous enum

anonymous enum : int

Possible bias settings.

Enumerator
BIAS_AS_IS	Line's bias state is unknown.
BIAS_DISABLE	Line's internal bias is disabled.
BIAS_PULL_UP	Line's internal pull-up bias is enabled.
BIAS_PULL_DOWN	Line's internal pull-down bias is enabled.

Definition at line 510 of file gpiod.hpp.

Constructor & Destructor Documentation

◆ line() [1/3]

GPIOD_API gpiod::line::line ( void )

Default constructor.

Creates an empty line object.

◆ line() [2/3]

GPIOD_API gpiod::line::line ( const line & other )

default

Copy constructor.

Parameters

other Other line object.

◆ line() [3/3]

GPIOD_API gpiod::line::line ( line && other )

default

Move constructor.

Parameters

other Other line object.

Member Function Documentation

◆ active_state()

GPIOD_API int gpiod::line::active_state ( void ) const

Get current active state of this line.

Returns: Current active state setting.

◆ bias()

GPIOD_API int gpiod::line::bias ( void ) const

Get current bias of this line.

Returns: Current bias setting.

◆ consumer()

GPIOD_API ::std::string gpiod::line::consumer ( void ) const

Get the consumer of this line (if any).

Returns: Name of the consumer of this line or an empty string if it is unused.

◆ direction()

GPIOD_API int gpiod::line::direction ( void ) const

Get current direction of this line.

Returns: Current direction setting.

◆ event_get_fd()

GPIOD_API int gpiod::line::event_get_fd ( void ) const

Get the event file descriptor associated with this line.

Returns: File descriptor number.

◆ event_read()

GPIOD_API line_event gpiod::line::event_read ( void ) const

Read a line event.

Returns: Line event object.

◆ event_read_multiple()

GPIOD_API ::std::vector<line_event> gpiod::line::event_read_multiple ( void ) const

Read multiple line events.

Returns: Vector of line event objects.

◆ event_wait()

GPIOD_API bool gpiod::line::event_wait ( const ::std::chrono::nanoseconds & timeout ) const

Wait for an event on this line.

Parameters

timeout Time to wait before returning if no event occurred.

Returns: True if an event occurred and can be read, false if the wait timed out.

◆ get_chip()

GPIOD_API const chip& gpiod::line::get_chip ( void ) const

Get the reference to the parent chip.

Returns: Reference to the parent chip object.

◆ get_value()

GPIOD_API int gpiod::line::get_value ( void ) const

Read the line value.

Returns: Current value (0 or 1).

◆ is_open_drain()

GPIOD_API bool gpiod::line::is_open_drain ( void ) const

Check if this line represents an open-drain GPIO.

Returns: True if the line is an open-drain GPIO, false otherwise.

◆ is_open_source()

GPIOD_API bool gpiod::line::is_open_source ( void ) const

Check if this line represents an open-source GPIO.

Returns: True if the line is an open-source GPIO, false otherwise.

◆ is_requested()

GPIOD_API bool gpiod::line::is_requested ( void ) const

Check if this user has ownership of this line.

Returns: True if the user has ownership of this line, false otherwise.

◆ is_used()

GPIOD_API bool gpiod::line::is_used ( void ) const

Check if this line is used by the kernel or other user space process.

Returns: True if this line is in use, false otherwise.

◆ name()

GPIOD_API ::std::string gpiod::line::name ( void ) const

Get the name of this line (if any).

Returns: Name of this line or an empty string if it is unnamed.

◆ offset()

GPIOD_API unsigned int gpiod::line::offset ( void ) const

Get the offset of this line.

Returns: Offet of this line.

◆ operator bool()

GPIOD_API gpiod::line::operator bool ( void ) const

explicitnoexcept

Check if this object holds a reference to any GPIO line.

Returns: True if this object references a GPIO line, false otherwise.

◆ operator!()

GPIOD_API bool gpiod::line::operator! ( void ) const

noexcept

Check if this object doesn't reference any GPIO line.

Returns: True if this object doesn't reference any GPIO line, true otherwise.

References DIRECTION_INPUT, and DIRECTION_OUTPUT.

◆ operator!=()

GPIOD_API bool gpiod::line::operator!= ( const line & rhs ) const

noexcept

Check if two line objects reference different GPIO lines.

Parameters

rhs	Right-hand side of the equation.

Returns: False if both objects reference the same line, true otherwise.

◆ operator=() [1/2]

GPIOD_API line& gpiod::line::operator= ( const line & other )

default

Assignment operator.

Parameters

other Other line object.

Returns: Reference to this object.

◆ operator=() [2/2]

GPIOD_API line& gpiod::line::operator= ( line && other )

default

Move assignment operator.

Parameters

other Other line object.

Returns: Reference to this object.

◆ operator==()

GPIOD_API bool gpiod::line::operator== ( const line & rhs ) const

noexcept

Check if two line objects reference the same GPIO line.

Parameters

rhs	Right-hand side of the equation.

Returns: True if both objects reference the same line, fale otherwise.

◆ request()

GPIOD_API void gpiod::line::request	(	const line_request &	config,
		int	default_val = `0`
	)		const

Request this line.

Parameters

config	Request config (see gpiod::line_request).
default_val	Default value - only matters for OUTPUT direction.

◆ reset()

GPIOD_API void gpiod::line::reset ( void )

Reset the state of this object.

This is useful when the user needs to e.g. keep the line_event object but wants to drop the reference to the GPIO chip indirectly held by the line being the source of the event.

◆ set_config()

GPIOD_API void gpiod::line::set_config	(	int	direction,
		::std::bitset< 32 >	flags,
		int	value = `0`
	)		const

Set configuration of this line.

Parameters

direction	New direction.
flags	Replacement flags.
value	New value (0 or 1) - only matters for OUTPUT direction.

◆ set_direction_output()

GPIOD_API void gpiod::line::set_direction_output ( int value = 0 ) const

Change the direction this lines to output.

Parameters

value New value (0 or 1).

◆ set_flags()

GPIOD_API void gpiod::line::set_flags ( ::std::bitset< 32 > flags ) const

Set configuration flags of this line.

Parameters

flags Replacement flags.

◆ set_value()

GPIOD_API void gpiod::line::set_value ( int val ) const

Set the value of this line.

Parameters

val	New value (0 or 1).

The documentation for this class was generated from the following file:

gpiod.hpp

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

◆ anonymous enum

◆ anonymous enum

Constructor & Destructor Documentation

◆ line() [1/3]

◆ line() [2/3]

◆ line() [3/3]

Member Function Documentation

◆ active_state()

◆ bias()

◆ consumer()

◆ direction()

◆ event_get_fd()

◆ event_read()

◆ event_read_multiple()

◆ event_wait()

◆ get_chip()

◆ get_value()

◆ is_open_drain()

◆ is_open_source()

◆ is_requested()

◆ is_used()

◆ name()

◆ offset()

◆ operator bool()

◆ operator!()

◆ operator!=()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()

◆ request()

◆ reset()

◆ set_config()

◆ set_direction_output()

◆ set_flags()

◆ set_value()