package ocaml-base-compiler
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sha256=c2d706432f93ba85bd3383fa451d74543c32a4e84a1afaf3e8ace18f7f097b43
doc/stdlib/Stdlib/In_channel/index.html
Module Stdlib.In_channel
Source
Input channels.
The type of input channel.
type open_flag = open_flag =
| Open_rdonly
(*open for reading.
*)| Open_wronly
(*open for writing.
*)| Open_append
(*open for appending: always write at end of file.
*)| Open_creat
(*create the file if it does not exist.
*)| Open_trunc
(*empty the file if it already exists.
*)| Open_excl
(*fail if Open_creat and the file already exists.
*)| Open_binary
(*open in binary mode (no conversion).
*)| Open_text
(*open in text mode (may perform conversions).
*)| Open_nonblock
(*open in non-blocking mode.
*)
Opening modes for open_gen
.
Open the named file for reading, and return a new input channel on that file, positioned at the beginning of the file.
with_open_bin fn f
opens a channel ic
on file fn
and returns f ic
. After f
returns, either with a value or by raising an exception, ic
is guaranteed to be closed.
Like with_open_bin
, but the channel is opened in text mode (see open_text
).
Like with_open_bin
, but can specify the opening mode and file permission, in case the file must be created (see open_gen
).
seek chan pos
sets the current reading position to pos
for channel chan
. This works only for regular files. On files of other kinds, the behavior is unspecified.
Return the current reading position for the given channel. For files opened in text mode under Windows, the returned position is approximate (owing to end-of-line conversion); in particular, saving the current position with pos
, then going back to this position using seek
will not work. For this programming idiom to work reliably and portably, the file must be opened in binary mode.
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.
Close the given channel. Input functions raise a Sys_error
exception when they are applied to a closed input channel, except close
, which does nothing when applied to an already closed channel.
Read one character from the given input channel. Returns None
if there are no more characters to read.
Same as input_char
, but return the 8-bit integer representing the character. Returns None
if the end of file was reached.
input_line ic
reads characters from ic
until a newline or the end of file is reached. Returns the string of all characters read, without the newline (if any). Returns None
if the end of the file has been reached. In particular, this will be the case if the last line of input is empty.
A newline is the character \n
unless the file is open in text mode and Sys.win32
is true
in which case it is the sequence of characters \r\n
.
input ic buf pos len
reads up to len
characters from the given channel ic
, storing them in byte sequence buf
, starting at character number pos
. It returns the actual number of characters read, between 0 and len
(inclusive). A return value of 0 means that the end of file was reached.
Use really_input
to read exactly len
characters.
really_input ic buf pos len
reads len
characters from channel ic
, storing them in byte sequence buf
, starting at character number pos
.
Returns None
if the end of file is reached before len
characters have been read.
really_input_string ic len
reads len
characters from channel ic
and returns them in a new string. Returns None
if the end of file is reached before len
characters have been read.
set_binary_mode ic true
sets the channel ic
to binary mode: no translations take place during input.
set_binary_mode ic false
sets the channel ic
to text mode: depending on the operating system, some translations may take place during input. For instance, under Windows, end-of-lines will be translated from \r\n
to \n
.
This function has no effect under operating systems that do not distinguish between text mode and binary mode.