Module serctl

Data Types
Function Index
Function Details

Data Types

Function Index

baud/1	Return the constant defined for the baud rate for the platform.
cfsetispeed/2	Set the input speed of a serial device.
cfsetospeed/2	Set the input speed of the serial device.
close/1	Explicitly close a serial device.
constant/0	Map of atoms reprsenting terminal attribute constants to integers.
constant/1
flow/1	Get/set serial device flow control.
flow/2
getfd/1	Returns the file descriptor associated with the NIF resource.
getflag/3	Returns whether a flag is enabled.
init/0
ioctl/3	Perform operations controlling a serial device.
ispeed/1	return the input speed of a serial device.
ispeed/2
mode/1	Enable raw mode.
offset/2
open/1	Open a serial device.
ospeed/1	return the output speed of a serial device.
ospeed/2
read/2	Read from a serial device.
readx/2	Read the specified number of bytes from a serial device.
readx/3
setflag/2	Returns an Erlang termios record used for setting the attributes of a serial device.
tcgetattr/1	Get the terminal attributes of a serial device.
tcsetattr/3	Sets the terminal attributes of a serial device.
termios/1
wordalign/1
wordalign/2
write/2	Write data to a serial device.

Function Details

baud/1

baud(Speed) -> any()

Return the constant defined for the baud rate for the platform

cfsetispeed/2

cfsetispeed(Termios::termios(), Speed::atom() | integer()) -> binary()

Set the input speed of a serial device

See the warning for tcsetattr/2.

Failure: badarg if Speed is an invalid atom.

cfsetospeed/2

cfsetospeed(Termios::termios(), Speed::atom() | integer()) -> binary()

Set the input speed of the serial device.

See the warning for tcsetattr/2.

Failure: badarg if Speed is an invalid atom.

close/1

close(X1::fd()) -> {ok, fd()} | errno()

Explicitly close a serial device

The device is automatically closed if the process holding open the serial device exits.

constant/0

constant() -> proplists:proplist()

Map of atoms reprsenting terminal attribute constants to integers

Varies across platforms.

constant/1

constant(X1::atom()) -> integer() | undefined

flow/1

flow(Termios::<<_:64, _:_*8>> | #termios{}) -> boolean()

Get/set serial device flow control

flow/1 indicates whether flow control is enabled in a serial device's terminal attributes. flow/2 returns a termios structure that can be used for setting a serial device's flow control.

flow/2

flow(Termios::<<_:64, _:_*8>> | #termios{}, Bool::boolean()) -> #termios{}

getfd/1

getfd(X1::fd()) -> integer()

Returns the file descriptor associated with the NIF resource

The file descriptor can be used with erlang:open_port/2.

getflag/3

getflag(Termios::<<_:64, _:_*8>> | #termios{}, Flag::cflag | iflag | lflag | oflag, Opt::atom()) -> boolean()

Returns whether a flag is enabled

Opt is one of the atoms returned using serctl:constant/0.

ioctl/3

ioctl(X1::fd(), X2::integer(), X3::binary()) -> {ok, binary()} | errno()

Perform operations controlling a serial device

The In argument is a binary holding the input parameter to the device request. The Out parameter will hold the result of the request if the ioctl is in/out.

ispeed/1

ispeed(Speed::binary() | #termios{}) -> non_neg_integer()

return the input speed of a serial device

Note the speed returned is the constant defined for the system and may differ between platforms.

ispeed/2 returns an Erlang termios record that can be used for setting the input speed of the serial device.

Failure: badarg if Speed is an invalid atom.

ispeed/2

ispeed(Termios::<<_:64, _:_*8>> | #termios{}, Speed::atom() | integer()) -> <<_:8, _:_*8>> | #termios{}

mode/1

mode(X1) -> any()

Enable raw mode

Returns an Erlang termios record with attributes that can be used to put the serial device into raw mode.

open/1

open(Dev::dev()) -> {ok, fd()} | errno()

Open a serial device

A serial device is a character device such as /dev/ttyUSB0.

A previously opened file descriptor can also be used. The fd should be opened with the O_NONBLOCK|O_NOCTTY flags.

ospeed/1

ospeed(Speed::binary() | #termios{}) -> non_neg_integer()

return the output speed of a serial device

Note the speed returned is the constant defined for the system and may differ between platforms.

ospeed/2 returns an Erlang termios record that can be used for setting the output speed of the serial device.

Failure: badarg if Speed is an invalid atom.

ospeed/2

ospeed(Termios::<<_:64, _:_*8>> | #termios{}, Speed::atom() | integer()) -> <<_:8, _:_*8>> | #termios{}

read/2

read(X1::fd(), X2::non_neg_integer()) -> {ok, binary()} | errno()

Read from a serial device

Size is an unsigned long.

readx/2

readx(FD::fd(), N::non_neg_integer()) -> {ok, binary()} | errno()

Read the specified number of bytes from a serial device

readx/2 will block forever.

readx/3 accepts a timeout value. The behaviour of readx/3 when the timeout is reached is to throw away any buffered data and return {error, eintr} to the caller, e.g., the caller will not be returned the contents of a partial read. (The justification for this behaviour: the caller has stated they require a fixed number of bytes so the contents of a partial read represents unspecified behaviour.)

readx/3

readx(FD::fd(), N::non_neg_integer(), Timeout::timeout()) -> {ok, binary()} | errno()

setflag/2

setflag(Termios::binary() | #termios{}, Opt::proplists:proplist()) -> #termios{}

Returns an Erlang termios record used for setting the attributes of a serial device

For example, to create attributes that can be used to enable hardware flow control on a serial device:

 {ok, FD} = serctl:open("/dev/ttyUSB0"),
 {ok, Termios} = serctl:tcgetattr(FD),
 Termios1 = serctl:setflag(Termios, [{cflag, [{crtscts, true}]}]),
 ok = serctl:tcsetattr(FD, tcsanow, Termios1).

tcgetattr/1

tcgetattr(X1::fd()) -> {ok, binary()} | errno()

Get the terminal attributes of a serial device

Returns the contents of the system struct termios as a binary.

tcsetattr/3

tcsetattr(FD::fd(), Action::[atom()] | atom() | integer(), Termios::termios()) -> ok | errno() | {error, unsupported}

Sets the terminal attributes of a serial device

'tcsasoft' is a non-portable, BSD action. tcsetattr/3 will return {error,unsupported} on other platforms. Warning: the contents of Termios are passed directly to tcsettr(3). If the system tcsettr(3) does not perform any validation of the structure, it is possible the Erlang VM may crash.

Partial writes return the number of bytes written.

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