Module Stdio.In_channel

An input channel for doing blocking reads from input sources like files and sockets.

Note that an In_channel.t is a custom block with a finalizer, and so is allocated directly to the major heap. Creating a lot of in_channels can result in many major collections and poor performance.

Note that this is simply another interface on the in_channel type in the OCaml standard library.

type t = Caml.in_channel
include Base.Equal.S with type t := t
val equal : t Base.Equal.equal
val stdin : t
val create : ?⁠binary:Base.bool -> Base.string -> t
val with_file : ?⁠binary:Base.bool -> Base.string -> f:(t -> 'a) -> 'a

with_file ~f fname executes ~f on the open channel from fname, and closes it afterwards.

val close : t -> Base.unit

close t closes t, or does nothing if t is already closed, and may raise an exception.

val input : t -> buf:Base.bytes -> pos:Base.int -> len:Base.int -> Base.int
val really_input : t -> buf:Base.bytes -> pos:Base.int -> len:Base.int -> Base.unit Base.option
val really_input_exn : t -> buf:Base.bytes -> pos:Base.int -> len:Base.int -> Base.unit

Same as Pervasives.really_input, for backwards compatibility

val input_char : t -> Base.char Base.option

Read one character from the given input channel. Return None if there are no more characters to read.

val input_byte : t -> Base.int Base.option

Same as input_char, but return the 8-bit integer representing the character. Return None if an end of file was reached.

val input_binary_int : t -> Base.int Base.option

Read an integer encoded in binary format (4 bytes, big-endian) from the given input channel. See Pervasives.output_binary_int. Return None if an end of file was reached while reading the integer.

val unsafe_input_value : t -> _ Base.option

Ocaml's built-in marshal format

val input_buffer : t -> Base.Buffer.t -> len:Base.int -> Base.unit Base.option

input_buffer t buf ~len reads at most len characters from the input channel t and stores them at the end of buffer buf. Return None if the channel contains fewer than len characters. In this case, the characters are still added to the buffer, so as to avoid loss of data.

val input_all : t -> Base.string
val input_line : ?⁠fix_win_eol:Base.bool -> t -> Base.string Base.option

input_line ?fix_win_eol t reads a line from t and returns it, without the newline ("\n") character at the end, and, if fix_win_eol the trailing "\r\n" is dropped.

val input_line_exn : ?⁠fix_win_eol:Base.bool -> t -> Base.string
val fold_lines : ?⁠fix_win_eol:Base.bool -> t -> init:'a -> f:('a -> Base.string -> 'a) -> 'a

fold_lines ?fix_win_eol t ~init ~f folds over the lines read from t using input_line. Lines are provided to f in the order they are found in the file.

val input_lines : ?⁠fix_win_eol:Base.bool -> t -> Base.string Base.list

Completely reads an input channel and returns the results as a list of strings. Each line in one string.

val iter_lines : ?⁠fix_win_eol:Base.bool -> t -> f:(Base.string -> Base.unit) -> Base.unit

iter_lines ?fix_win_eol t ~f applies f to each line read from t using input_line.

val seek : t -> Base.int64 -> Base.unit

This works only for regular files. On files of other kinds, the behavior is unspecified.

val pos : t -> Base.int64
val length : t -> Base.int64

Return the size (number of characters) of the regular file on which the given channel is opened. If the channel is opened on a file that is not a regular file, the result is meaningless. The returned size does not take into account the end-of-line translations that can be performed when reading from a channel opened in text mode.

val set_binary_mode : t -> Base.bool -> Base.unit

same as Pervasives.set_binary_mode_in, only applicable for Windows or Cygwin, no-op otherwise

val read_lines : ?⁠fix_win_eol:Base.bool -> Base.string -> Base.string Base.list

read_lines filename reads the full contents of file and returns it as a list of lines, closing the file when it's done. It's the equivalent of with_file fname ~f:input_lines

val read_all : Base.string -> Base.string

read_all filename reads the full contents of file and returns it as a single string, closing the file when it's done. It's the equivalent of with_file fname ~f:input_all