GPIO chip

class chip

Represents a GPIO chip.

Public Functions

explicit chip(const ::std::filesystem::path &path)

Instantiates a new chip object by opening the device file indicated by the path argument.

chip(chip &&other) noexcept

Move constructor.

chip &operator=(chip &&other) noexcept

Move assignment operator.

explicit operator bool() const noexcept

Check if this object is valid.

Returns:: True if this object’s methods can be used, false otherwise. False usually means the chip was closed. If the user calls any of the methods of this class on an object for which this operator returned false, a logic_error will be thrown.

void close(): Close the GPIO chip device file and free associated resources.

Note

The chip object can live after calling this method but any of the chip’s mutators will throw a logic_error exception.

::std::filesystem::path path() const

Get the filesystem path that was used to open this GPIO chip.

chip_info get_info() const

Get information about the chip.

line_info get_line_info(line::offset offset) const

Retrieve the current snapshot of line information for a single line.

line_info watch_line_info(line::offset offset) const

Wrapper around gpiod::chip::get_line_info that retrieves the line info and starts watching the line for changes.

void unwatch_line_info(line::offset offset) const

Stop watching the line at given offset for info events.

int fd() const

Get the file descriptor associated with this chip.

bool wait_info_event(const ::std::chrono::nanoseconds &timeout) const

Wait for line status events on any of the watched lines exposed by this chip.

Parameters:: timeout – Wait time limit in nanoseconds. If set to 0, the function returns immediately. If set to a negative number, the function blocks indefinitely until an event becomes available.
Returns:: True if at least one event is ready to be read. False if the wait timed out.

info_event read_info_event() const

Read a single line status change event from this chip.

int get_line_offset_from_name(const ::std::string &name) const

Map a GPIO line’s name to its offset within the chip.

Parameters:: name – Name of the GPIO line to map.
Returns:: Offset of the line within the chip or -1 if the line with given name is not exposed by this chip.

Create a request_builder associated with this chip.