Module Stdlib
Contents
Instructions: Use this module in your project
In the IDE (CLion, Visual Studio Code, Xcode, etc.) you use for your DkSDK project:
Add the following to your project's
dependencies/CMakeLists.txt
:DkSDKProject_DeclareAvailable(ocaml CONSTRAINT "= 4.14.0" FINDLIBS str unix runtime_events threads dynlink) DkSDKProject_MakeAvailable(ocaml)
Add the
Findlib::ocaml
library to any desired targets insrc/*/CMakeLists.txt
:target_link_libraries(YourPackage_YourLibraryName # ... existing libraries, if any ... Findlib::ocaml)
Click your IDE's
Build
button
Not using DkSDK?
FIRST, do one or all of the following:
Run:
opam install ocaml.4.14.0
Edit your
dune-project
and add:(package (name YourExistingPackage) (depends ; ... existing dependenices ... (ocaml (>= 4.14.0))))
Then run:
dune build *.opam # if this fails, run: dune build
Edit your
<package>.opam
file and add:depends: [ # ... existing dependencies ... "ocaml" {>= "4.14.0"} ]
Then run:
opam install . --deps-only
FINALLY, add the library to any desired
(library)
and/or (executable)
targets in your **/dune
files:
(library
(name YourLibrary)
; ... existing library options ...
(libraries
; ... existing libraries ...
))
(executable
(name YourExecutable)
; ... existing executable options ...
(libraries
; ... existing libraries ...
))
Exceptions
val
raise : ``exn
->
'a
Raise the given exception value
val
raise_notrace : ``exn
->
'a
A faster version raise
which does not record the backtrace.
- since 4.02.0
val
invalid_arg : ``string
->
'a
Raise exception Invalid_argument
with the given string.
val
failwith : ``string
->
'a
Raise exception Failure
with the given string.
exception
Exit
The Exit
exception is not raised by any library function. It is
provided for use in your programs.
exception
Match_failure
of
string * int * int
Exception raised when none of the cases of a pattern-matching apply. The arguments are the location of the match keyword in the source code (file name, line number, column number).
exception
Assert_failure
of
string * int * int
Exception raised when an assertion fails. The arguments are the location of the assert keyword in the source code (file name, line number, column number).
exception
Invalid_argument
of
string
Exception raised by library functions to signal that the given arguments do not make sense. The string gives some information to the programmer. As a general rule, this exception should not be caught, it denotes a programming error and the code should be modified not to trigger it.
exception
Failure
of
string
Exception raised by library functions to signal that they are undefined on the given arguments. The string is meant to give some information to the programmer; you must not pattern match on the string literal because it may change in future versions (use Failure _ instead).
exception
Not_found
Exception raised by search functions when the desired object could not be found.
exception
Out_of_memory
Exception raised by the garbage collector when there is insufficient memory to complete the computation. (Not reliable for allocations on the minor heap.)
exception
Stack_overflow
Exception raised by the bytecode interpreter when the evaluation stack reaches its maximal size. This often indicates infinite or excessively deep recursion in the user's program.
Before 4.10, it was not fully implemented by the native-code compiler.
exception
Sys_error
of
string
Exception raised by the input/output functions to report an operating system error. The string is meant to give some information to the programmer; you must not pattern match on the string literal because it may change in future versions (use Sys_error _ instead).
exception
End_of_file
Exception raised by input functions to signal that the end of file has been reached.
exception
Division_by_zero
Exception raised by integer division and remainder operations when their second argument is zero.
exception
Sys_blocked_io
A special case of Sys_error raised when no I/O is possible on a non-blocking I/O channel.
exception
Undefined_recursive_module
of
string * int * int
Exception raised when an ill-founded recursive module definition is evaluated. The arguments are the location of the definition in the source code (file name, line number, column number).
Comparisons
val
(=) :
'a
->
'a
->
bool
e1 = e2
tests for structural equality of e1
and e2
. Mutable
structures (e.g. references and arrays) are equal if and only if their
current contents are structurally equal, even if the two mutable objects
are not the same physical object. Equality between functional values
raises Invalid_argument
. Equality between cyclic data structures may
not terminate. Left-associative operator, see Ocaml_operators
for more
information.
val
(<>) :
'a
->
'a
->
bool
Negation of Stdlib.(=)
. Left-associative operator, see
Ocaml_operators
for more information.
val
(<) :
'a
->
'a
->
bool
See Stdlib.(>=)
. Left-associative operator, see
Ocaml_operators
for more information.
val
(>) :
'a
->
'a
->
bool
See Stdlib.(>=)
. Left-associative operator, see
Ocaml_operators
for more information.
val
(<=) :
'a
->
'a
->
bool
See Stdlib.(>=)
. Left-associative operator, see
Ocaml_operators
for more information.
val
(>=) :
'a
->
'a
->
bool
Structural ordering functions. These functions coincide with the usual
orderings over integers, characters, strings, byte sequences and
floating-point numbers, and extend them to a total ordering over all
types. The ordering is compatible with ( = )
. As in the case of
( = )
, mutable structures are compared by contents. Comparison between
functional values raises Invalid_argument
. Comparison between cyclic
structures may not terminate. Left-associative operator, see
Ocaml_operators
for more information.
val
compare :
'a
->
'a
->
int
compare x y
returns 0
if x
is equal to y
, a negative integer if
x
is less than y
, and a positive integer if x
is greater than y
.
The ordering implemented by compare
is compatible with the comparison
predicates =
, <
and >
defined above, with one difference on the
treatment of the float value Stdlib.nan
. Namely, the
comparison predicates treat nan
as different from any other float
value, including itself; while compare
treats nan
as equal to itself
and less than any other float value. This treatment of nan
ensures
that compare
defines a total ordering relation.
compare
applied to functional values may raise Invalid_argument
.
compare
applied to cyclic structures may not terminate.
The compare
function can be used as the comparison function required
by the Set.Make
and
Map.Make
functors, as well as the
List.sort
and
Array.sort
functions.
val
min :
'a
->
'a
->
'a
Return the smaller of the two arguments. The result is unspecified if
one of the arguments contains the float value nan
.
val
max :
'a
->
'a
->
'a
Return the greater of the two arguments. The result is unspecified if
one of the arguments contains the float value nan
.
val
(==) :
'a
->
'a
->
bool
e1 == e2
tests for physical equality of e1
and e2
. On mutable
types such as references, arrays, byte sequences, records with mutable
fields and objects with mutable instance variables, e1 == e2
is true
if and only if physical modification of e1
also affects e2
. On
non-mutable types, the behavior of ( == )
is implementation-dependent;
however, it is guaranteed that e1 == e2
implies compare e1 e2 = 0
.
Left-associative operator, see Ocaml_operators
for more information.
val
(!=) :
'a
->
'a
->
bool
Negation of Stdlib.(==)
. Left-associative operator, see
Ocaml_operators
for more information.
Boolean operations
val
not : ``bool
->
bool
The boolean negation.
val
(&&) : ``bool
->
``bool
->
bool
The boolean 'and'. Evaluation is sequential, left-to-right: in
e1 && e2
, e1
is evaluated first, and if it returns false
, e2
is
not evaluated at all. Right-associative operator, see Ocaml_operators
for more information.
val
(&) : ``bool
->
``bool
->
bool
-
deprecated
Stdlib.(&&)
should be used instead. Right-associative operator, seeOcaml_operators
for more information.
val
(||) : ``bool
->
``bool
->
bool
The boolean 'or'. Evaluation is sequential, left-to-right: in
e1 || e2
, e1
is evaluated first, and if it returns true
, e2
is
not evaluated at all. Right-associative operator, see Ocaml_operators
for more information.
val
or : ``bool
->
``bool
->
bool
-
deprecated
Stdlib.(||)
should be used instead. Right-associative operator, seeOcaml_operators
for more information.
Debugging
val
__LOC__ : string
__LOC__
returns the location at which this expression appears in the
file currently being parsed by the compiler, with the standard error
format of OCaml: "File %S, line %d, characters %d-%d".
- since 4.02.0
val
__FILE__ : string
__FILE__
returns the name of the file currently being parsed by the
compiler.
- since 4.02.0
val
__LINE__ : int
__LINE__
returns the line number at which this expression appears in
the file currently being parsed by the compiler.
- since 4.02.0
val
__MODULE__ : string
__MODULE__
returns the module name of the file being parsed by the
compiler.
- since 4.02.0
val
__POS__ : string * int * int * int
__POS__
returns a tuple (file,lnum,cnum,enum)
, corresponding to the
location at which this expression appears in the file currently being
parsed by the compiler. file
is the current filename, lnum
the line
number, cnum
the character position in the line and enum
the last
character position in the line.
- since 4.02.0
val
__FUNCTION__ : string
__FUNCTION__
returns the name of the current function or method,
including any enclosing modules or classes.
- since 4.12.0
val
__LOC_OF__ :
'a
->
string *
'a
__LOC_OF__ expr
returns a pair (loc, expr)
where loc
is the
location of expr
in the file currently being parsed by the compiler,
with the standard error format of OCaml: "File %S, line %d, characters
%d-%d".
- since 4.02.0
val
__LINE_OF__ :
'a
->
int *
'a
__LINE_OF__ expr
returns a pair (line, expr)
, where line
is the
line number at which the expression expr
appears in the file currently
being parsed by the compiler.
- since 4.02.0
val
__POS_OF__ :
'a
->
``(string * int * int * int)`` *
'a
__POS_OF__ expr
returns a pair (loc,expr)
, where loc
is a tuple
(file,lnum,cnum,enum)
corresponding to the location at which the
expression expr
appears in the file currently being parsed by the
compiler. file
is the current filename, lnum
the line number, cnum
the character position in the line and enum
the last character
position in the line.
- since 4.02.0
Composition operators
val
(|>) :
'a
->
``(
'a
->
'b
)``
->
'b
Reverse-application operator: x |> f |> g
is exactly equivalent to
g (f (x))
. Left-associative operator, see Ocaml_operators
for more
information.
- since 4.01
val
(@@) : ``(
'a
->
'b
)``
->
'a
->
'b
Application operator: g @@ f @@ x
is exactly equivalent to
g (f (x))
. Right-associative operator, see Ocaml_operators
for more
information.
- since 4.01
Integer arithmetic
Integers are Sys.int_size
bits wide. All operations are taken modulo
2Sys.int_size
. They do not fail on overflow.
val
(~-) : ``int
->
int
Unary negation. You can also write - e
instead of ~- e
. Unary
operator, see Ocaml_operators
for more information.
val
(~+) : ``int
->
int
Unary addition. You can also write + e
instead of ~+ e
. Unary
operator, see Ocaml_operators
for more information.
- since 3.12.0
val
succ : ``int
->
int
succ x
is x + 1
.
val
pred : ``int
->
int
pred x
is x - 1
.
val
(+) : ``int
->
``int
->
int
Integer addition. Left-associative operator, see Ocaml_operators
for
more information.
val
(-) : ``int
->
``int
->
int
Integer subtraction. Left-associative operator, , see Ocaml_operators
for more information.
val
(*) : ``int
->
``int
->
int
Integer multiplication. Left-associative operator, see Ocaml_operators
for more information.
val
(/) : ``int
->
``int
->
int
Integer division. Integer division rounds the real quotient of its
arguments towards zero. More precisely, if x >= 0
and y > 0
, x / y
is the greatest integer less than or equal to the real quotient of x
by y
. Moreover, (- x) / y = x / (- y) = - (x / y)
. Left-associative
operator, see Ocaml_operators
for more information.
-
raises Division_by_zero
if the second argument is 0.
val
(mod) : ``int
->
``int
->
int
Integer remainder. If y
is not zero, the result of x mod y
satisfies
the following properties: x = (x / y) * y + x mod y
and
abs(x mod y) <= abs(y) - 1
. If y = 0
, x mod y
raises
Division_by_zero
. Note that x mod y
is negative only if x < 0
.
Left-associative operator, see Ocaml_operators
for more information.
-
raises Division_by_zero
if
y
is zero.
val
abs : ``int
->
int
Return the absolute value of the argument. Note that this may be
negative if the argument is min_int
.
val
max_int : int
The greatest representable integer.
val
min_int : int
The smallest representable integer.
Bitwise operations
val
(land) : ``int
->
``int
->
int
Bitwise logical and. Left-associative operator, see Ocaml_operators
for more information.
val
(lor) : ``int
->
``int
->
int
Bitwise logical or. Left-associative operator, see Ocaml_operators
for
more information.
val
(lxor) : ``int
->
``int
->
int
Bitwise logical exclusive or. Left-associative operator, see
Ocaml_operators
for more information.
val
lnot : ``int
->
int
Bitwise logical negation.
val
(lsl) : ``int
->
``int
->
int
n lsl m
shifts n
to the left by m
bits. The result is unspecified
if m < 0
or m > Sys.int_size
. Right-associative operator, see
Ocaml_operators
for more information.
val
(lsr) : ``int
->
``int
->
int
n lsr m
shifts n
to the right by m
bits. This is a logical shift:
zeroes are inserted regardless of the sign of n
. The result is
unspecified if m < 0
or m > Sys.int_size
. Right-associative
operator, see Ocaml_operators
for more information.
val
(asr) : ``int
->
``int
->
int
n asr m
shifts n
to the right by m
bits. This is an arithmetic
shift: the sign bit of n
is replicated. The result is unspecified if
m < 0
or m > Sys.int_size
. Right-associative operator, see
Ocaml_operators
for more information.
Floating-point arithmetic
OCaml's floating-point numbers follow the IEEE 754 standard, using
double precision (64 bits) numbers. Floating-point operations never
raise an exception on overflow, underflow, division by zero, etc.
Instead, special IEEE numbers are returned as appropriate, such as
infinity
for 1.0 /. 0.0
, neg_infinity
for -1.0 /. 0.0
, and nan
('not a number') for 0.0 /. 0.0
. These special numbers then propagate
through floating-point computations as expected: for instance,
1.0 /. infinity
is 0.0
, basic arithmetic operations (+.
, -.
,
*.
, /.
) with nan
as an argument return nan
, ...
val
(~-.) : ``float
->
float
Unary negation. You can also write -. e
instead of ~-. e
. Unary
operator, see Ocaml_operators
for more information.
val
(~+.) : ``float
->
float
Unary addition. You can also write +. e
instead of ~+. e
. Unary
operator, see Ocaml_operators
for more information.
- since 3.12.0
val
(+.) : ``float
->
``float
->
float
Floating-point addition. Left-associative operator, see
Ocaml_operators
for more information.
val
(-.) : ``float
->
``float
->
float
Floating-point subtraction. Left-associative operator, see
Ocaml_operators
for more information.
val
(*.) : ``float
->
``float
->
float
Floating-point multiplication. Left-associative operator, see
Ocaml_operators
for more information.
val
(/.) : ``float
->
``float
->
float
Floating-point division. Left-associative operator, see
Ocaml_operators
for more information.
val
(**) : ``float
->
``float
->
float
Exponentiation. Right-associative operator, see Ocaml_operators
for
more information.
val
sqrt : ``float
->
float
Square root.
val
exp : ``float
->
float
Exponential.
val
log : ``float
->
float
Natural logarithm.
val
log10 : ``float
->
float
Base 10 logarithm.
val
expm1 : ``float
->
float
expm1 x
computes exp x -. 1.0
, giving numerically-accurate results
even if x
is close to 0.0
.
- since 3.12.0
val
log1p : ``float
->
float
log1p x
computes log(1.0 +. x)
(natural logarithm), giving
numerically-accurate results even if x
is close to 0.0
.
- since 3.12.0
val
cos : ``float
->
float
Cosine. Argument is in radians.
val
sin : ``float
->
float
Sine. Argument is in radians.
val
tan : ``float
->
float
Tangent. Argument is in radians.
val
acos : ``float
->
float
Arc cosine. The argument must fall within the range [-1.0, 1.0]
.
Result is in radians and is between 0.0
and pi
.
val
asin : ``float
->
float
Arc sine. The argument must fall within the range [-1.0, 1.0]
. Result
is in radians and is between -pi/2
and pi/2
.
val
atan : ``float
->
float
Arc tangent. Result is in radians and is between -pi/2
and pi/2
.
val
atan2 : ``float
->
``float
->
float
atan2 y x
returns the arc tangent of y /. x
. The signs of x
and
y
are used to determine the quadrant of the result. Result is in
radians and is between -pi
and pi
.
val
hypot : ``float
->
``float
->
float
hypot x y
returns sqrt(x *. x + y *. y)
, that is, the length of the
hypotenuse of a right-angled triangle with sides of length x
and y
,
or, equivalently, the distance of the point (x,y)
to origin. If one of
x
or y
is infinite, returns infinity
even if the other is nan
.
- since 4.00.0
val
cosh : ``float
->
float
Hyperbolic cosine. Argument is in radians.
val
sinh : ``float
->
float
Hyperbolic sine. Argument is in radians.
val
tanh : ``float
->
float
Hyperbolic tangent. Argument is in radians.
val
acosh : ``float
->
float
Hyperbolic arc cosine. The argument must fall within the range
[1.0, inf]
. Result is in radians and is between 0.0
and inf
.
- since 4.13.0
val
asinh : ``float
->
float
Hyperbolic arc sine. The argument and result range over the entire real line. Result is in radians.
- since 4.13.0
val
atanh : ``float
->
float
Hyperbolic arc tangent. The argument must fall within the range
[-1.0, 1.0]
. Result is in radians and ranges over the entire real
line.
- since 4.13.0
val
ceil : ``float
->
float
Round above to an integer value. ceil f
returns the least integer
value greater than or equal to f
. The result is returned as a float.
val
floor : ``float
->
float
Round below to an integer value. floor f
returns the greatest integer
value less than or equal to f
. The result is returned as a float.
val
abs_float : ``float
->
float
abs_float f
returns the absolute value of f
.
val
copysign : ``float
->
``float
->
float
copysign x y
returns a float whose absolute value is that of x
and
whose sign is that of y
. If x
is nan
, returns nan
. If y
is
nan
, returns either x
or -. x
, but it is not specified which.
- since 4.00.0
val
mod_float : ``float
->
``float
->
float
mod_float a b
returns the remainder of a
with respect to b
. The
returned value is a -. n *. b
, where n
is the quotient a /. b
rounded towards zero to an integer.
val
frexp : ``float
->
float * int
frexp f
returns the pair of the significant and the exponent of f
.
When f
is zero, the significant x
and the exponent n
of f
are
equal to zero. When f
is non-zero, they are defined by
f = x *. 2 ** n
and 0.5 <= x < 1.0
.
val
ldexp : ``float
->
``int
->
float
ldexp x n
returns x *. 2 ** n
.
val
modf : ``float
->
float * float
modf f
returns the pair of the fractional and integral part of f
.
val
float : ``int
->
float
Same as Stdlib.float_of_int
.
val
float_of_int : ``int
->
float
Convert an integer to floating-point.
val
truncate : ``float
->
int
Same as Stdlib.int_of_float
.
val
int_of_float : ``float
->
int
Truncate the given floating-point number to an integer. The result is
unspecified if the argument is nan
or falls outside the range of
representable integers.
val
infinity : float
Positive infinity.
val
neg_infinity : float
Negative infinity.
val
nan : float
A special floating-point value denoting the result of an undefined
operation such as 0.0 /. 0.0
. Stands for 'not a number'. Any
floating-point operation with nan
as argument returns nan
as result.
As for floating-point comparisons, =
, <
, <=
, >
and >=
return
false
and <>
returns true
if one or both of their arguments is
nan
.
val
max_float : float
The largest positive finite value of type float
.
val
min_float : float
The smallest positive, non-zero, non-denormalized value of type float
.
val
epsilon_float : float
The difference between 1.0
and the smallest exactly representable
floating-point number greater than 1.0
.
type
fpclass`` =
|
FP_normal
(* Normal number, none of the below
*)
|
FP_subnormal
(* Number very close to 0.0, has reduced precision
*)
|
FP_zero
(* Number is 0.0 or -0.0
*)
|
FP_infinite
(* Number is positive or negative infinity
*)
|
FP_nan
(* Not a number: result of an undefined operation
*)
The five classes of floating-point numbers, as determined by the
Stdlib.classify_float
function.
val
classify_float : ``float
->
fpclass
Return the class of the given floating-point number: normal, subnormal, zero, infinite, or not a number.
String operations
More string operations are provided in module
String
.
val
(^) : ``string
->
``string
->
string
String concatenation. Right-associative operator, see Ocaml_operators
for more information.
-
raises Invalid_argument
if the result is longer then than
Sys.max_string_length
bytes.
Character operations
More character operations are provided in module
Char
.
val
int_of_char : ``char
->
int
Return the ASCII code of the argument.
val
char_of_int : ``int
->
char
Return the character with the given ASCII code.
-
raises Invalid_argument
if the argument is outside the range 0--255.
Unit operations
val
ignore :
'a
->
unit
Discard the value of its argument and return ()
. For instance,
ignore(f x)
discards the result of the side-effecting function f
. It
is equivalent to f x; ()
, except that the latter may generate a
compiler warning; writing ignore(f x)
instead avoids the warning.
String conversion functions
val
string_of_bool : ``bool
->
string
Return the string representation of a boolean. As the returned values may be shared, the user should not modify them directly.
val
bool_of_string_opt : ``string
->
``bool option
Convert the given string to a boolean.
Return None
if the string is not "true"
or "false"
.
- since 4.05
val
bool_of_string : ``string
->
bool
Same as Stdlib.bool_of_string_opt
, but
raise Invalid_argument "bool_of_string"
instead of returning None
.
val
string_of_int : ``int
->
string
Return the string representation of an integer, in decimal.
val
int_of_string_opt : ``string
->
``int option
Convert the given string to an integer. The string is read in decimal
(by default, or if the string begins with 0u
), in hexadecimal (if it
begins with 0x
or 0X
), in octal (if it begins with 0o
or 0O
), or
in binary (if it begins with 0b
or 0B
).
The 0u
prefix reads the input as an unsigned integer in the range
[0, 2*max_int+1]
. If the input exceeds max_int
it is
converted to the signed integer min_int + input - max_int - 1
.
The _
(underscore) character can appear anywhere in the string and is
ignored.
Return None
if the given string is not a valid representation of an
integer, or if the integer represented exceeds the range of integers
representable in type int
.
- since 4.05
val
int_of_string : ``string
->
int
Same as Stdlib.int_of_string_opt
, but raise
Failure "int_of_string"
instead of returning None
.
val
string_of_float : ``float
->
string
Return the string representation of a floating-point number.
val
float_of_string_opt : ``string
->
``float option
Convert the given string to a float. The string is read in decimal (by
default) or in hexadecimal (marked by 0x
or 0X
).
The format of decimal floating-point numbers is
[-] dd.ddd (e|E) [+|-] dd
, where d
stands for a decimal digit.
The format of hexadecimal floating-point numbers is
[-] 0(x|X) hh.hhh (p|P) [+|-] dd
, where h
stands for an
hexadecimal digit and d
for a decimal digit.
In both cases, at least one of the integer and fractional parts must be given; the exponent part is optional.
The _
(underscore) character can appear anywhere in the string and is
ignored.
Depending on the execution platforms, other representations of floating-point numbers can be accepted, but should not be relied upon.
Return None
if the given string is not a valid representation of a
float.
- since 4.05
val
float_of_string : ``string
->
float
Same as Stdlib.float_of_string_opt
, but
raise Failure "float_of_string"
instead of returning None
.
Pair operations
val
fst : ``(
'a
*
'b
)``
->
'a
Return the first component of a pair.
val
snd : ``(
'a
*
'b
)``
->
'b
Return the second component of a pair.
List operations
More list operations are provided in module List
.
val
(@) :
'a
list``
->
'a
list``
->
'a
list
List concatenation. Not tail-recursive (length of the first argument).
Right-associative operator, see Ocaml_operators
for more information.
Input/output
Note: all input/output functions can raise Sys_error
when the system
calls they invoke fail.
type
in_channel
The type of input channel.
type
out_channel
The type of output channel.
val
stdin :
in_channel
The standard input for the process.
val
stdout :
out_channel
The standard output for the process.
val
stderr :
out_channel
The standard error output for the process.
Output functions on standard output
val
print_char : ``char
->
unit
Print a character on standard output.
val
print_string : ``string
->
unit
Print a string on standard output.
val
print_bytes : ``bytes
->
unit
Print a byte sequence on standard output.
- since 4.02.0
val
print_int : ``int
->
unit
Print an integer, in decimal, on standard output.
val
print_float : ``float
->
unit
Print a floating-point number, in decimal, on standard output.
val
print_endline : ``string
->
unit
Print a string, followed by a newline character, on standard output and flush standard output.
val
print_newline : ``unit
->
unit
Print a newline character on standard output, and flush standard output. This can be used to simulate line buffering of standard output.
Output functions on standard error
val
prerr_char : ``char
->
unit
Print a character on standard error.
val
prerr_string : ``string
->
unit
Print a string on standard error.
val
prerr_bytes : ``bytes
->
unit
Print a byte sequence on standard error.
- since 4.02.0
val
prerr_int : ``int
->
unit
Print an integer, in decimal, on standard error.
val
prerr_float : ``float
->
unit
Print a floating-point number, in decimal, on standard error.
val
prerr_endline : ``string
->
unit
Print a string, followed by a newline character on standard error and flush standard error.
val
prerr_newline : ``unit
->
unit
Print a newline character on standard error, and flush standard error.
Input functions on standard input
val
read_line : ``unit
->
string
Flush standard output, then read characters from standard input until a newline character is encountered.
Return the string of all characters read, without the newline character at the end.
-
raises End_of_file
if the end of the file is reached at the beginning of line.
val
read_int_opt : ``unit
->
``int option
Flush standard output, then read one line from standard input and convert it to an integer.
Return None
if the line read is not a valid representation of an
integer.
- since 4.05
val
read_int : ``unit
->
int
Same as Stdlib.read_int_opt
, but raise
Failure "int_of_string"
instead of returning None
.
val
read_float_opt : ``unit
->
``float option
Flush standard output, then read one line from standard input and convert it to a floating-point number.
Return None
if the line read is not a valid representation of a
floating-point number.
- since 4.05.0
val
read_float : ``unit
->
float
Same as Stdlib.read_float_opt
, but raise
Failure "float_of_string"
instead of returning None
.
General output functions
type
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 Stdlib.open_out_gen
and
Stdlib.open_in_gen
.
val
open_out : ``string
->
out_channel
Open the named file for writing, and return a new output channel on that file, positioned at the beginning of the file. The file is truncated to zero length if it already exists. It is created if it does not already exists.
val
open_out_bin : ``string
->
out_channel
Same as Stdlib.open_out
, but the file is opened in
binary mode, so that no translation takes place during writes. On
operating systems that do not distinguish between text mode and binary
mode, this function behaves like Stdlib.open_out
.
val
open_out_gen :
open_flag
list``
->
``int
->
``string
->
out_channel
open_out_gen mode perm filename
opens the named file for writing, as
described above. The extra argument mode
specifies the opening mode.
The extra argument perm
specifies the file permissions, in case the
file must be created. Stdlib.open_out
and
Stdlib.open_out_bin
are special cases of this
function.
val
flush :
out_channel
->
unit
Flush the buffer associated with the given output channel, performing all pending writes on that channel. Interactive programs must be careful about flushing standard output and standard error at the right time.
val
flush_all : ``unit
->
unit
Flush all open output channels; ignore errors.
val
output_char :
out_channel
->
``char
->
unit
Write the character on the given output channel.
val
output_string :
out_channel
->
``string
->
unit
Write the string on the given output channel.
val
output_bytes :
out_channel
->
``bytes
->
unit
Write the byte sequence on the given output channel.
- since 4.02.0
val
output :
out_channel
->
``bytes
->
``int
->
``int
->
unit
output oc buf pos len
writes len
characters from byte sequence
buf
, starting at offset pos
, to the given output channel oc
.
-
raises Invalid_argument
if
pos
andlen
do not designate a valid range ofbuf
.
val
output_substring :
out_channel
->
``string
->
``int
->
``int
->
unit
Same as output
but take a string as argument instead of a byte
sequence.
- since 4.02.0
val
output_byte :
out_channel
->
``int
->
unit
Write one 8-bit integer (as the single character with that code) on the given output channel. The given integer is taken modulo 256.
val
output_binary_int :
out_channel
->
``int
->
unit
Write one integer in binary format (4 bytes, big-endian) on the given
output channel. The given integer is taken modulo 232. The
only reliable way to read it back is through the
Stdlib.input_binary_int
function. The format
is compatible across all machines for a given version of OCaml.
val
output_value :
out_channel
->
'a
->
unit
Write the representation of a structured value of any type to a channel.
Circularities and sharing inside the value are detected and preserved.
The object can be read back, by the function
Stdlib.input_value
. See the description of module
Marshal
for more information.
Stdlib.output_value
is equivalent to
Marshal.to_channel
with an empty
list of flags.
val
seek_out :
out_channel
->
``int
->
unit
seek_out chan pos
sets the current writing position to pos
for
channel chan
. This works only for regular files. On files of other
kinds (such as terminals, pipes and sockets), the behavior is
unspecified.
val
pos_out :
out_channel
->
int
Return the current writing position for the given channel. Does not work
on channels opened with the Open_append
flag (returns unspecified
results). 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_out
, then going back
to this position using seek_out
will not work. For this programming
idiom to work reliably and portably, the file must be opened in binary
mode.
val
out_channel_length :
out_channel
->
int
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.
val
close_out :
out_channel
->
unit
Close the given channel, flushing all buffered write operations. Output
functions raise a Sys_error
exception when they are applied to a
closed output channel, except close_out
and flush
, which do nothing
when applied to an already closed channel. Note that close_out
may
raise Sys_error
if the operating system signals an error when flushing
or closing.
val
close_out_noerr :
out_channel
->
unit
Same as close_out
, but ignore all errors.
val
set_binary_mode_out :
out_channel
->
``bool
->
unit
set_binary_mode_out oc true
sets the channel oc
to binary mode: no
translations take place during output. set_binary_mode_out oc false
sets the channel oc
to text mode: depending on the operating system,
some translations may take place during output. For instance, under
Windows, end-of-lines will be translated from \n
to \r\n
. This
function has no effect under operating systems that do not distinguish
between text mode and binary mode.
General input functions
val
open_in : ``string
->
in_channel
Open the named file for reading, and return a new input channel on that file, positioned at the beginning of the file.
val
open_in_bin : ``string
->
in_channel
Same as Stdlib.open_in
, but the file is opened in
binary mode, so that no translation takes place during reads. On
operating systems that do not distinguish between text mode and binary
mode, this function behaves like Stdlib.open_in
.
val
open_in_gen :
open_flag
list``
->
``int
->
``string
->
in_channel
open_in_gen mode perm filename
opens the named file for reading, as
described above. The extra arguments mode
and perm
specify the
opening mode and file permissions. Stdlib.open_in
and
Stdlib.open_in_bin
are special cases of this
function.
val
input_char :
in_channel
->
char
Read one character from the given input channel.
-
raises End_of_file
if there are no more characters to read.
val
input_line :
in_channel
->
string
Read characters from the given input channel, until a newline character is encountered. Return the string of all characters read, without the newline character at the end.
-
raises End_of_file
if the end of the file is reached at the beginning of line.
val
input :
in_channel
->
``bytes
->
``int
->
``int
->
int
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. A return value between 0 and len
exclusive means that not
all requested len
characters were read, either because no more
characters were available at that time, or because the implementation
found it convenient to do a partial read; input
must be called again
to read the remaining characters, if desired. (See also
Stdlib.really_input
for reading exactly len
characters.) Exception Invalid_argument "input"
is raised if pos
and
len
do not designate a valid range of buf
.
val
really_input :
in_channel
->
``bytes
->
``int
->
``int
->
unit
really_input ic buf pos len
reads len
characters from channel ic
,
storing them in byte sequence buf
, starting at character number pos
.
-
raises End_of_file
if the end of file is reached before
len
characters have been read. -
raises Invalid_argument
if
pos
andlen
do not designate a valid range ofbuf
.
val
really_input_string :
in_channel
->
``int
->
string
really_input_string ic len
reads len
characters from channel ic
and returns them in a new string.
-
raises End_of_file
if the end of file is reached before
len
characters have been read. -
since 4.02.0
val
input_byte :
in_channel
->
int
Same as Stdlib.input_char
, but return the 8-bit
integer representing the character.
-
raises End_of_file
if the end of file was reached.
val
input_binary_int :
in_channel
->
int
Read an integer encoded in binary format (4 bytes, big-endian) from the
given input channel. See
Stdlib.output_binary_int
.
-
raises End_of_file
if the end of file was reached while reading the integer.
val
input_value :
in_channel
->
'a
Read the representation of a structured value, as produced by
Stdlib.output_value
, and return the corresponding
value. This function is identical to
Marshal.from_channel
; see the
description of module Marshal
for more
information, in particular concerning the lack of type safety.
val
seek_in :
in_channel
->
``int
->
unit
seek_in 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.
val
pos_in :
in_channel
->
int
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_in
, then going back to this position using seek_in
will not work. For this programming idiom to work reliably and portably,
the file must be opened in binary mode.
val
in_channel_length :
in_channel
->
int
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
close_in :
in_channel
->
unit
Close the given channel. Input functions raise a Sys_error
exception
when they are applied to a closed input channel, except close_in
,
which does nothing when applied to an already closed channel.
val
close_in_noerr :
in_channel
->
unit
Same as close_in
, but ignore all errors.
val
set_binary_mode_in :
in_channel
->
``bool
->
unit
set_binary_mode_in ic true
sets the channel ic
to binary mode: no
translations take place during input. set_binary_mode_out 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.
Operations on large files
module
LargeFile
:
sig
...
end
Operations on large files. This sub-module provides 64-bit variants of
the channel functions that manipulate file positions and file sizes. By
representing positions and sizes by 64-bit integers (type int64
)
instead of regular integers (type int
), these alternate functions
allow operating on files whose sizes are greater than max_int
.
References
type
``'a ref`` = ``{
mutable
contents :
'a
;
}
The type of references (mutable indirection cells) containing a value of
type 'a
.
val
ref :
'a
->
'a
ref
Return a fresh reference containing the given value.
val
(!) :
'a
ref
->
'a
!r
returns the current contents of reference r
. Equivalent to
fun r -> r.contents
. Unary operator, see Ocaml_operators
for more
information.
val
(:=) :
'a
ref
->
'a
->
unit
r := a
stores the value of a
in reference r
. Equivalent to
fun r v -> r.contents <- v
. Right-associative operator, see
Ocaml_operators
for more information.
val
incr : ``int
ref
->
unit
Increment the integer contained in the given reference. Equivalent to
fun r -> r := succ !r
.
val
decr : ``int
ref
->
unit
Decrement the integer contained in the given reference. Equivalent to
fun r -> r := pred !r
.
Result type
type
``('a, 'b) result`` =
|
Ok
of
'a
|
Error
of
'b
- since 4.03.0
Operations on format strings
Format strings are character strings with special lexical conventions
that defines the functionality of formatted input/output functions.
Format strings are used to read data with formatted input functions from
module Scanf
and to print data with formatted
output functions from modules Printf
and
Format
.
Format strings are made of three kinds of entities:
- conversions specifications, introduced by the special character
'%'
followed by one or more characters specifying what kind of argument to read or print, - formatting indications, introduced by the special character
'@'
followed by one or more characters specifying how to read or print the argument, - plain characters that are regular characters with usual lexical conventions. Plain characters specify string literals to be read in the input or printed in the output.
There is an additional lexical rule to escape the special characters
'%'
and '@'
in format strings: if a special character follows a
'%'
character, it is treated as a plain character. In other words,
"%%"
is considered as a plain '%'
and "%@"
as a plain '@'
.
For more information about conversion specifications and formatting
indications available, read the documentation of modules
Scanf
, Printf
and
Format
.
Format strings have a general and highly polymorphic type
('a, 'b, 'c, 'd, 'e, 'f) format6
. The two simplified types, format
and format4
below are included for backward compatibility with earlier
releases of OCaml.
The meaning of format string type parameters is as follows:
-
'a
is the type of the parameters of the format for formatted output functions (printf
-style functions);'a
is the type of the values read by the format for formatted input functions (scanf
-style functions). -
'b
is the type of input source for formatted input functions and the type of output target for formatted output functions. Forprintf
-style functions from modulePrintf
,'b
is typicallyout_channel
; forprintf
-style functions from moduleFormat
,'b
is typicallyFormat.formatter
; forscanf
-style functions from moduleScanf
,'b
is typicallyScanf.Scanning.in_channel
.
Type argument 'b
is also the type of the first argument given to
user's defined printing functions for %a
and %t
conversions, and
user's defined reading functions for %r
conversion.
-
'c
is the type of the result of the%a
and%t
printing functions, and also the type of the argument transmitted to the first argument ofkprintf
-style functions or to thekscanf
-style functions. -
'd
is the type of parameters for thescanf
-style functions. -
'e
is the type of the receiver function for thescanf
-style functions. -
'f
is the final result type of a formatted input/output function invocation: for theprintf
-style functions, it is typicallyunit
; for thescanf
-style functions, it is typically the result type of the receiver function.
type
``('a, 'b, 'c, 'd, 'e, 'f) format6`` = ``(
'a
,
'b
,
'c
,
'd
,
'e
,
'f
)``
CamlinternalFormatBasics.format6
type
``('a, 'b, 'c, 'd) format4`` = ``(
'a
,
'b
,
'c
,
'c
,
'c
,
'd
)``
format6
type
``('a, 'b, 'c) format`` = ``(
'a
,
'b
,
'c
,
'c
)``
format4
val
string_of_format : ``(
'a
,
'b
,
'c
,
'd
,
'e
,
'f
)``
format6
->
string
Converts a format string into a string.
format_of_string s
returns a format string read from the string
literal s
. Note: format_of_string
can not convert a string argument
that is not a literal. If you need this functionality, use the more
general
Scanf.format_from_string
function.
val
(^^) : ``(
'a
,
'b
,
'c
,
'd
,
'e
,
'f
)``
format6
->
``(
'f
,
'b
,
'c
,
'e
,
'g
,
'h
)``
format6
->
``(
'a
,
'b
,
'c
,
'd
,
'g
,
'h
)``
format6
f1 ^^ f2
catenates format strings f1
and f2
. The result is a
format string that behaves as the concatenation of format strings f1
and f2
: in case of formatted output, it accepts arguments from f1
,
then arguments from f2
; in case of formatted input, it returns results
from f1
, then results from f2
. Right-associative operator, see
Ocaml_operators
for more information.
Program termination
val
exit : ``int
->
'a
Terminate the process, returning the given status code to the operating
system: usually 0 to indicate no errors, and a small positive integer to
indicate failure. All open output channels are flushed with flush_all
.
An implicit exit 0
is performed each time a program terminates
normally. An implicit exit 2
is performed if the program terminates
early because of an uncaught exception.
val
at_exit : ``(``unit
->
unit)``
->
unit
Register the given function to be called at program termination time.
The functions registered with at_exit
will be called when the program
does any of the following:
- executes
Stdlib.exit
- terminates, either normally or because of an uncaught exception
- executes the C function
caml_shutdown
. The functions are called in 'last in, first out' order: the function most recently added withat_exit
is called first.
Standard library modules
module
Arg
:
sig
...
end
Parsing of command line arguments.
module
Array
:
sig
...
end
Array operations.
module
ArrayLabels
:
sig
...
end
Array operations.
module
Atomic
:
sig
...
end
This module provides a purely sequential implementation of the concurrent atomic references provided by the Multicore OCaml standard library:
module
Bigarray
:
sig
...
end
Large, multi-dimensional, numerical arrays.
module
Bool
:
sig
...
end
Boolean values.
module
Buffer
:
sig
...
end
Extensible buffers.
module
Bytes
:
sig
...
end
Byte sequence operations.
module
BytesLabels
:
sig
...
end
Byte sequence operations.
module
Callback
:
sig
...
end
Registering OCaml values with the C runtime.
module
Char
:
sig
...
end
Character operations.
module
Complex
:
sig
...
end
Complex numbers.
module
Digest
:
sig
...
end
MD5 message digest.
module
Either
:
sig
...
end
Either type.
module
Ephemeron
:
sig
...
end
Ephemerons and weak hash tables.
module
Filename
:
sig
...
end
Operations on file names.
module
Float
:
sig
...
end
Floating-point arithmetic.
module
Format
:
sig
...
end
Pretty-printing.
module
Fun
:
sig
...
end
Function manipulation.
module
Gc
:
sig
...
end
Memory management control and statistics; finalised values.
module
Genlex
:
sig
...
end
module
Hashtbl
:
sig
...
end
Hash tables and hash functions.
module
In_channel
:
sig
...
end
Input channels.
module
Int
:
sig
...
end
Integer values.
module
Int32
:
sig
...
end
32-bit integers.
module
Int64
:
sig
...
end
64-bit integers.
module
Lazy
:
sig
...
end
Deferred computations.
module
Lexing
:
sig
...
end
The run-time library for lexers generated by ocamllex
.
module
List
:
sig
...
end
List operations.
module
ListLabels
:
sig
...
end
List operations.
module
Map
:
sig
...
end
Association tables over ordered types.
module
Marshal
:
sig
...
end
Marshaling of data structures.
module
MoreLabels
:
sig
...
end
Extra labeled libraries.
module
Nativeint
:
sig
...
end
Processor-native integers.
module
Obj
:
sig
...
end
Operations on internal representations of values.
module
Oo
:
sig
...
end
Operations on objects
module
Option
:
sig
...
end
Option values.
module
Out_channel
:
sig
...
end
Output channels.
module
Parsing
:
sig
...
end
The run-time library for parsers generated by ocamlyacc
.
module
Pervasives
:
sig
...
end
module
Printexc
:
sig
...
end
Facilities for printing exceptions and inspecting current call stack.
module
Printf
:
sig
...
end
Formatted output functions.
module
Queue
:
sig
...
end
First-in first-out queues.
module
Random
:
sig
...
end
Pseudo-random number generators (PRNG).
module
Result
:
sig
...
end
Result values.
module
Scanf
:
sig
...
end
Formatted input functions.
module
Seq
:
sig
...
end
Sequences.
module
Set
:
sig
...
end
Sets over ordered types.
module
Stack
:
sig
...
end
Last-in first-out stacks.
module
StdLabels
:
sig
...
end
Standard labeled libraries.
module
Stream
:
sig
...
end
module
String
:
sig
...
end
Strings.
module
StringLabels
:
sig
...
end
Strings.
module
Sys
:
sig
...
end
System interface.
module
Uchar
:
sig
...
end
Unicode characters.
module
Unit
:
sig
...
end
Unit values.
module
Weak
:
sig
...
end
Arrays of weak pointers and hash sets of weak pointers.