class IO::FileDescriptor

Overview

An IO over a file descriptor.

Included Modules

Direct Known Subclasses

Defined in:

io/console.cr
io/file_descriptor.cr

Constructors

Class Method Summary

Instance Method Summary

Macro Summary

Instance methods inherited from module IO::Buffered

buffer_size : Int32 buffer_size, buffer_size=(value) buffer_size=, close : Nil close, flush flush, flush_on_newline=(flush_on_newline) flush_on_newline=, flush_on_newline? : Bool flush_on_newline?, peek : Bytes peek, pos : Int64 pos, read(slice : Bytes) : Int32 read, read_buffering=(read_buffering) read_buffering=, read_buffering? : Bool read_buffering?, rewind rewind, sync=(sync) sync=, sync? : Bool sync?, unbuffered_close unbuffered_close, unbuffered_flush unbuffered_flush, unbuffered_read(slice : Bytes) unbuffered_read, unbuffered_rewind unbuffered_rewind, unbuffered_write(slice : Bytes) unbuffered_write, write(slice : Bytes) : Nil write

Instance methods inherited from module Crystal::System::FileDescriptor

file_descriptor_close : Nil file_descriptor_close

Class methods inherited from module Crystal::System::FileDescriptor

cfmakeraw(termios_p) cfmakeraw, fcntl(fd, cmd, arg = 0) fcntl, from_stdio(fd) from_stdio, pipe(read_blocking, write_blocking) pipe, pread(fd, buffer, offset) pread, system_info(fd) system_info, tcgetattr(fd) tcgetattr, tcsetattr(fd, optional_actions, termios_p) tcsetattr

Instance methods inherited from module IO::Evented

evented_close : Nil evented_close, evented_read(slice : Bytes, errno_msg : String, &) : Int32 evented_read, evented_reopen : Nil evented_reopen, evented_send(slice : Bytes, errno_msg : String, &) : Int32 evented_send, evented_write(slice : Bytes, errno_msg : String, &) : Nil evented_write, read_timeout : Time::Span | Nil read_timeout, read_timeout=(read_timeout : Number) : Number
read_timeout=(timeout : Time::Span | Nil) : Time::Span | Nil
read_timeout=
, write_timeout : Time::Span | Nil write_timeout, write_timeout=(write_timeout : Number) : Number
write_timeout=(timeout : Time::Span | Nil) : Time::Span | Nil
write_timeout=

Instance methods inherited from class IO

<<(obj) : self <<, close close, closed? : Bool closed?, each_byte(&) : Nil
each_byte
each_byte
, each_char(&) : Nil
each_char
each_char
, each_line(*args, **options, &block : String -> ) : Nil
each_line(*args, **options)
each_line
, encoding : String encoding, flush flush, getb_to_end : Bytes getb_to_end, gets(limit : Int, chomp = false) : String | Nil
gets(delimiter : Char, limit : Int, chomp = false) : String | Nil
gets(delimiter : Char, chomp = false) : String | Nil
gets(delimiter : String, chomp = false) : String | Nil
gets(chomp = true) : String | Nil
gets
, gets_to_end : String gets_to_end, peek : Bytes | Nil peek, pos pos, pos=(value) pos=, print(obj : _) : Nil
print(*objects : _) : Nil
print
, printf(format_string, args : Array | Tuple) : Nil
printf(format_string, *args) : Nil
printf
, puts(string : String) : Nil
puts(obj : _) : Nil
puts : Nil
puts(*objects : _) : Nil
puts
, read(slice : Bytes) read, read_at(offset, bytesize, & : IO -> ) read_at, read_byte : UInt8 | Nil read_byte, read_bytes(type, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) read_bytes, read_char : Char | Nil read_char, read_fully(slice : Bytes) : Int32 read_fully, read_fully?(slice : Bytes) : Int32 | Nil read_fully?, read_line(*args, **options) : String read_line, read_string(bytesize : Int) : String read_string, read_utf8(slice : Bytes) read_utf8, read_utf8_byte : UInt8 | Nil read_utf8_byte, rewind rewind, seek(offset, whence : Seek = Seek::Set) seek, set_encoding(encoding : String, invalid : Symbol | Nil = nil) : Nil set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tell tell, tty? : Bool tty?, write(slice : Bytes) : Nil write, write_byte(byte : UInt8) : Nil write_byte, write_bytes(object, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) : Nil write_bytes, write_string(slice : Bytes) : Nil write_string, write_utf8(slice : Bytes) : Nil write_utf8

Class methods inherited from class IO

copy(src, dst, limit : Int) : Int64
copy(src, dst) : Int64
copy
, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &)
pipe
, same_content?(stream1 : IO, stream2 : IO) : Bool same_content?

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other)
==
, dup dup, hash(hasher) hash, initialize initialize, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference) : Bool
same?(other : Nil)
same?
, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other)
===
, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash
hash
, in?(collection : Object) : Bool
in?(*values : Object) : Bool
in?
, inspect(io : IO) : Nil
inspect : String
inspect
, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil!
not_nil!
, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String
to_json
, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil
to_pretty_json
, to_s(io : IO) : Nil
to_s : String
to_s
, to_yaml(io : IO) : Nil
to_yaml : String
to_yaml
, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io)
from_json
, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def self.new(fd, blocking = nil, *, close_on_finalize : Bool = true) #

[View source]

Class Method Detail

def self.fcntl(fd, cmd, arg = 0) #

[View source]

Instance Method Detail

def blocking #

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def blocking=(value) #

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def close_on_exec=(value : Bool) #

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def close_on_exec? : Bool #

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def close_on_finalize=(close_on_finalize : Bool) #

Whether or not to close the file descriptor when this object is finalized. Disabling this is useful in order to create an IO wrapper over a file descriptor returned from a C API that keeps ownership of the descriptor. Do note that, if the fd is closed by its owner at any point, any IO operations will then fail.


[View source]
def close_on_finalize? : Bool #

Whether or not to close the file descriptor when this object is finalized. Disabling this is useful in order to create an IO wrapper over a file descriptor returned from a C API that keeps ownership of the descriptor. Do note that, if the fd is closed by its owner at any point, any IO operations will then fail.


[View source]
def closed? : Bool #
Description copied from class IO

Returns true if this IO is closed.

IO defines returns false, but including types may override.


[View source]
def cooked(& : self -> _) #

Yields self to the given block, enables character processing for the duration of the block, and returns the block's value.

The so called cooked mode is the standard behavior of a terminal, doing line wise editing by the terminal and only sending the input to the program on a newline.

Raises IO::Error if this IO is not a terminal device.


[View source]
def cooked! : Nil #

Enables character processing on this IO.

The so called cooked mode is the standard behavior of a terminal, doing line wise editing by the terminal and only sending the input to the program on a newline.

Raises IO::Error if this IO is not a terminal device.


[View source]
def echo(& : self -> _) #

Yields self to the given block, enables character echoing for the duration of the block, and returns the block's value.

This causes user input to be displayed as they are entered on the terminal.

Raises IO::Error if this IO is not a terminal device.


[View source]
def echo! : Nil #

Enables character echoing on this IO.

This causes user input to be displayed as they are entered on the terminal.

Raises IO::Error if this IO is not a terminal device.


[View source]
def fcntl(cmd, arg = 0) #

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def fd : Int #

The raw file-descriptor. It is defined to be an Int, but its size is platform-specific.


[View source]
def finalize #

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def flock_exclusive(blocking = true, &) #

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def flock_exclusive(blocking = true) : Nil #

Places an exclusive advisory lock. Only one process may hold an exclusive lock for a given file descriptor at a given time. IO::Error is raised if blocking is set to false and any existing lock is set.


[View source]
def flock_shared(blocking = true, &) #

[View source]
def flock_shared(blocking = true) : Nil #

Places a shared advisory lock. More than one process may hold a shared lock for a given file descriptor at a given time. IO::Error is raised if blocking is set to false and an existing exclusive lock is set.


[View source]
def flock_unlock : Nil #

Removes an existing advisory lock held by this process.


[View source]
def fsync(flush_metadata = true) : Nil #

Flushes all data written to this File Descriptor to the disk device so that all changed information can be retrieved even if the system crashes or is rebooted. The call blocks until the device reports that the transfer has completed. To reduce disk activity the flush_metadata parameter can be set to false, then the syscall fdatasync will be used and only data required for subsequent data retrieval is flushed. Metadata such as modified time and access time is not written.

NOTE Metadata is flushed even when flush_metadata is false on Windows and DragonFly BSD.


[View source]
def info : File::Info #

Returns a File::Info object for this file descriptor, or raises IO::Error in case of an error.

Certain fields like the file size may not be updated until an explicit flush.

File.write("testfile", "abc")

file = File.new("testfile", "a")
file.info.size # => 3
file << "defgh"
file.info.size # => 3
file.flush
file.info.size # => 8

Use File.info if the file is not open and a path to the file is available.


[View source]
def inspect(io : IO) : Nil #
Description copied from class Reference

Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.

class Person
  def initialize(@name : String, @age : Int32)
  end
end

Person.new("John", 32).inspect # => #<Person:0x10fd31f20 @name="John", @age=32>

[View source]
def noecho(& : self -> _) #

Yields self to the given block, disables character echoing for the duration of the block, and returns the block's value.

This will prevent displaying back to the user what they enter on the terminal.

Raises IO::Error if this IO is not a terminal device.

print "Enter password: "
password = STDIN.noecho &.gets.try &.chomp
puts

[View source]
def noecho! : Nil #

Disables character echoing on this IO.

This will prevent displaying back to the user what they enter on the terminal.

Raises IO::Error if this IO is not a terminal device.


[View source]
def pos=(value) #

Sets the current position (in bytes) in this IO.

File.write("testfile", "hello")

file = File.new("testfile")
file.pos = 3
file.gets_to_end # => "lo"

[View source]
def pretty_print(pp) #

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def raw(& : self -> _) #

Yields self to the given block, enables raw mode for the duration of the block, and returns the block's value.

In raw mode every keypress is directly sent to the program, no interpretation is done by the terminal. On Windows, this also enables ANSI input escape sequences.

Raises IO::Error if this IO is not a terminal device.


[View source]
def raw! : Nil #

Enables raw mode on this IO.

In raw mode every keypress is directly sent to the program, no interpretation is done by the terminal. On Windows, this also enables ANSI input escape sequences.

Raises IO::Error if this IO is not a terminal device.


[View source]
def reopen(other : IO::FileDescriptor) #

[View source]
def seek(offset, whence : Seek = Seek::Set) #

Seeks to a given offset (in bytes) according to the whence argument. Returns self.

File.write("testfile", "abc")

file = File.new("testfile")
file.gets(3) # => "abc"
file.seek(1, IO::Seek::Set)
file.gets(2) # => "bc"
file.seek(-1, IO::Seek::Current)
file.gets(1) # => "c"

[View source]
def seek(offset, whence : Seek = Seek::Set, &) #

Same as #seek but yields to the block after seeking and eventually seeks back to the original position when the block returns.


[View source]
def tty? : Bool #
Description copied from class IO

Returns true if this IO is associated with a terminal device (tty), false otherwise.

IO returns false, but including types may override.

STDIN.tty?          # => true
IO::Memory.new.tty? # => false

[View source]

Macro Detail

macro cooked_from_tc_mode! #

DEPRECATED


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macro noecho_from_tc_mode! #

DEPRECATED


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macro raw_from_tc_mode! #

DEPRECATED


[View source]