.TH "Scanf.Scanning" 3o source: 2019-01-25 OCamldoc "OCaml library"
.SH NAME
Scanf.Scanning \- no description
.SH Module
Module   Scanf.Scanning
.SH Documentation
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Module
.BI "Scanning"
 : 
.B sig  end

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.I type in_channel 

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The notion of input channel for the 
.B Scanf
module:
those channels provide all the machinery necessary to read from any source
of characters, including a 
.B Pervasives\&.in_channel
value\&.
A Scanf\&.Scanning\&.in_channel value is also called a formatted input
channel or equivalently a scanning buffer\&.
The type 
.B Scanf\&.Scanning\&.scanbuf
below is an alias for 
.B Scanning\&.in_channel
\&.

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.B "Since"
3.12.0

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.I type scanbuf 
= 
.B in_channel

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The type of scanning buffers\&. A scanning buffer is the source from which a
formatted input function gets characters\&. The scanning buffer holds the
current state of the scan, plus a function to get the next char from the
input, and a token buffer to store the string matched so far\&.
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Note: a scanning action may often require to examine one character in
advance; when this \&'lookahead\&' character does not belong to the token
read, it is stored back in the scanning buffer and becomes the next
character yet to be read\&.

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.I val stdin 
: 
.B in_channel
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The standard input notion for the 
.B Scanf
module\&.
.B Scanning\&.stdin
is the 
.B Scanf\&.Scanning\&.in_channel
formatted input channel
attached to 
.B Pervasives\&.stdin
\&.
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Note: in the interactive system, when input is read from
.B Pervasives\&.stdin
, the newline character that triggers evaluation is
part of the input; thus, the scanning specifications must properly skip
this additional newline character (for instance, simply add a 
.B \&'\(rsn\&'
as
the last character of the format string)\&.

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.B "Since"
3.12.0

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.I type file_name 
= 
.B string

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A convenient alias to designate a file name\&.

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.B "Since"
4.00.0

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.I val open_in 
: 
.B file_name -> in_channel
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.B Scanning\&.open_in fname
returns a 
.B Scanf\&.Scanning\&.in_channel
formatted input
channel for bufferized reading in text mode from file 
.B fname
\&.
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Note:
.B open_in
returns a formatted input channel that efficiently reads
characters in large chunks; in contrast, 
.B from_channel
below returns
formatted input channels that must read one character at a time, leading
to a much slower scanning rate\&.

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.B "Since"
3.12.0

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.I val open_in_bin 
: 
.B file_name -> in_channel
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.B Scanning\&.open_in_bin fname
returns a 
.B Scanf\&.Scanning\&.in_channel
formatted
input channel for bufferized reading in binary mode from file 
.B fname
\&.

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.B "Since"
3.12.0

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.I val close_in 
: 
.B in_channel -> unit
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Closes the 
.B Pervasives\&.in_channel
associated with the given
.B Scanf\&.Scanning\&.in_channel
formatted input channel\&.

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.B "Since"
3.12.0

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.I val from_file 
: 
.B file_name -> in_channel
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An alias for 
.B Scanf\&.Scanning\&.open_in
above\&.

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.I val from_file_bin 
: 
.B string -> in_channel
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An alias for 
.B Scanf\&.Scanning\&.open_in_bin
above\&.

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.I val from_string 
: 
.B string -> in_channel
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.B Scanning\&.from_string s
returns a 
.B Scanf\&.Scanning\&.in_channel
formatted
input channel which reads from the given string\&.
Reading starts from the first character in the string\&.
The end\-of\-input condition is set when the end of the string is reached\&.

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.I val from_function 
: 
.B (unit -> char) -> in_channel
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.B Scanning\&.from_function f
returns a 
.B Scanf\&.Scanning\&.in_channel
formatted
input channel with the given function as its reading method\&.
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When scanning needs one more character, the given function is called\&.
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When the function has no more character to provide, it must signal an
end\-of\-input condition by raising the exception 
.B End_of_file
\&.

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.I val from_channel 
: 
.B Pervasives.in_channel -> in_channel
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.B Scanning\&.from_channel ic
returns a 
.B Scanf\&.Scanning\&.in_channel
formatted
input channel which reads from the regular 
.B Pervasives\&.in_channel
input
channel 
.B ic
argument\&.
Reading starts at current reading position of 
.B ic
\&.

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.I val end_of_input 
: 
.B in_channel -> bool
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.B Scanning\&.end_of_input ic
tests the end\-of\-input condition of the given
.B Scanf\&.Scanning\&.in_channel
formatted input channel\&.

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.I val beginning_of_input 
: 
.B in_channel -> bool
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.B Scanning\&.beginning_of_input ic
tests the beginning of input condition
of the given 
.B Scanf\&.Scanning\&.in_channel
formatted input channel\&.

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.I val name_of_input 
: 
.B in_channel -> string
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.B Scanning\&.name_of_input ic
returns the name of the character source
for the given 
.B Scanf\&.Scanning\&.in_channel
formatted input channel\&.

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.B "Since"
3.09.0

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.I val stdib 
: 
.B in_channel
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A deprecated alias for 
.B Scanf\&.Scanning\&.stdin
, the scanning buffer reading from
.B Pervasives\&.stdin
\&.

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