Primitive Type pointer1.0.0[−]
Raw, unsafe pointers, *const T
, and *mut T
.
Working with raw pointers in Rust is uncommon, typically limited to a few patterns.
Raw pointers can be unaligned or null
. However, when a raw pointer is
dereferenced (using the *
operator), it must be non-null and aligned.
Storing through a raw pointer using *ptr = data
calls drop
on the old value, so
write
must be used if the type has drop glue and memory is not already
initialized - otherwise drop
would be called on the uninitialized memory.
Use the null
and null_mut
functions to create null pointers, and the
is_null
method of the *const T
and *mut T
types to check for null.
The *const T
and *mut T
types also define the offset
method, for
pointer math.
Common ways to create raw pointers
1. Coerce a reference (&T
) or mutable reference (&mut T
).
let my_num: i32 = 10; let my_num_ptr: *const i32 = &my_num; let mut my_speed: i32 = 88; let my_speed_ptr: *mut i32 = &mut my_speed;Run
To get a pointer to a boxed value, dereference the box:
let my_num: Box<i32> = Box::new(10); let my_num_ptr: *const i32 = &*my_num; let mut my_speed: Box<i32> = Box::new(88); let my_speed_ptr: *mut i32 = &mut *my_speed;Run
This does not take ownership of the original allocation and requires no resource management later, but you must not use the pointer after its lifetime.
2. Consume a box (Box<T>
).
The into_raw
function consumes a box and returns
the raw pointer. It doesn't destroy T
or deallocate any memory.
let my_speed: Box<i32> = Box::new(88); let my_speed: *mut i32 = Box::into_raw(my_speed); // By taking ownership of the original `Box<T>` though // we are obligated to put it together later to be destroyed. unsafe { drop(Box::from_raw(my_speed)); }Run
Note that here the call to drop
is for clarity - it indicates
that we are done with the given value and it should be destroyed.
3. Get it from C.
extern crate libc; use std::mem; unsafe { let my_num: *mut i32 = libc::malloc(mem::size_of::<i32>()) as *mut i32; if my_num.is_null() { panic!("failed to allocate memory"); } libc::free(my_num as *mut libc::c_void); }Run
Usually you wouldn't literally use malloc
and free
from Rust,
but C APIs hand out a lot of pointers generally, so are a common source
of raw pointers in Rust.
Implementations
impl<T> *const T where
T: ?Sized,
[src]
T: ?Sized,
pub fn is_null(self) -> bool
[src]
Returns true
if the pointer is null.
Note that unsized types have many possible null pointers, as only the raw data pointer is considered, not their length, vtable, etc. Therefore, two pointers that are null may still not compare equal to each other.
Behavior during const evaluation
When this function is used during const evaluation, it may return false
for pointers
that turn out to be null at runtime. Specifically, when a pointer to some memory
is offset beyond its bounds in such a way that the resulting pointer is null,
the function will still return false
. There is no way for CTFE to know
the absolute position of that memory, so we cannot tell if the pointer is
null or not.
Examples
Basic usage:
let s: &str = "Follow the rabbit"; let ptr: *const u8 = s.as_ptr(); assert!(!ptr.is_null());Run
pub const fn cast<U>(self) -> *const U
1.38.0 (const: 1.38.0)[src]
Casts to a pointer of another type.
pub unsafe fn as_ref<'a>(self) -> Option<&'a T>
1.9.0[src]
Returns None
if the pointer is null, or else returns a shared reference to
the value wrapped in Some
. If the value may be uninitialized, as_uninit_ref
must be used instead.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be properly aligned.
-
It must be "dereferencable" in the sense defined in the module documentation.
-
The pointer must point to an initialized instance of
T
. -
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get mutated (except insideUnsafeCell
).
This applies even if the result of this method is unused! (The part about being initialized is not yet fully decided, but until it is, the only safe approach is to ensure that they are indeed initialized.)
Examples
Basic usage:
let ptr: *const u8 = &10u8 as *const u8; unsafe { if let Some(val_back) = ptr.as_ref() { println!("We got back the value: {}!", val_back); } }Run
Null-unchecked version
If you are sure the pointer can never be null and are looking for some kind of
as_ref_unchecked
that returns the &T
instead of Option<&T>
, know that you can
dereference the pointer directly.
let ptr: *const u8 = &10u8 as *const u8; unsafe { let val_back = &*ptr; println!("We got back the value: {}!", val_back); }Run
pub unsafe fn as_uninit_ref<'a>(self) -> Option<&'a MaybeUninit<T>>
[src]
Returns None
if the pointer is null, or else returns a shared reference to
the value wrapped in Some
. In contrast to as_ref
, this does not require
that the value has to be initialized.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be properly aligned.
-
It must be "dereferencable" in the sense defined in the module documentation.
-
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get mutated (except insideUnsafeCell
).
This applies even if the result of this method is unused!
Examples
Basic usage:
#![feature(ptr_as_uninit)] let ptr: *const u8 = &10u8 as *const u8; unsafe { if let Some(val_back) = ptr.as_uninit_ref() { println!("We got back the value: {}!", val_back.assume_init()); } }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub unsafe fn offset(self, count: isize) -> *const T
[src]
Calculates the offset from a pointer.
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and resulting pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
The computed offset, in bytes, cannot overflow an
isize
. -
The offset being in bounds cannot rely on "wrapping around" the address space. That is, the infinite-precision sum, in bytes must fit in a usize.
The compiler and standard library generally tries to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
vec.as_ptr().add(vec.len())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Consider using wrapping_offset
instead if these constraints are
difficult to satisfy. The only advantage of this method is that it
enables more aggressive compiler optimizations.
Examples
Basic usage:
let s: &str = "123"; let ptr: *const u8 = s.as_ptr(); unsafe { println!("{}", *ptr.offset(1) as char); println!("{}", *ptr.offset(2) as char); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn wrapping_offset(self, count: isize) -> *const T
1.16.0[src]
Calculates the offset from a pointer using wrapping arithmetic.
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
This operation itself is always safe, but using the resulting pointer is not.
The resulting pointer remains attached to the same allocated object that self
points to.
It may not be used to access a different allocated object. Note that in Rust, every
(stack-allocated) variable is considered a separate allocated object.
In other words, let z = x.wrapping_offset((y as isize) - (x as isize))
does not make z
the same as y
even if we assume T
has size 1
and there is no overflow: z
is still
attached to the object x
is attached to, and dereferencing it is Undefined Behavior unless
x
and y
point into the same allocated object.
Compared to offset
, this method basically delays the requirement of staying within the
same allocated object: offset
is immediate Undefined Behavior when crossing object
boundaries; wrapping_offset
produces a pointer but still leads to Undefined Behavior if a
pointer is dereferenced when it is out-of-bounds of the object it is attached to. offset
can be optimized better and is thus preferable in performance-sensitive code.
The delayed check only considers the value of the pointer that was dereferenced, not the
intermediate values used during the computation of the final result. For example,
x.wrapping_offset(o).wrapping_offset(o.wrapping_neg())
is always the same as x
. In other
words, leaving the allocated object and then re-entering it later is permitted.
If you need to cross object boundaries, cast the pointer to an integer and do the arithmetic there.
Examples
Basic usage:
// Iterate using a raw pointer in increments of two elements let data = [1u8, 2, 3, 4, 5]; let mut ptr: *const u8 = data.as_ptr(); let step = 2; let end_rounded_up = ptr.wrapping_offset(6); // This loop prints "1, 3, 5, " while ptr != end_rounded_up { unsafe { print!("{}, ", *ptr); } ptr = ptr.wrapping_offset(step); }Run
pub unsafe fn offset_from(self, origin: *const T) -> isize
1.47.0[src]
Calculates the distance between two pointers. The returned value is in
units of T: the distance in bytes is divided by mem::size_of::<T>()
.
This function is the inverse of offset
.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and other pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
Both pointers must be derived from a pointer to the same object. (See below for an example.)
-
The distance between the pointers, in bytes, cannot overflow an
isize
. -
The distance between the pointers, in bytes, must be an exact multiple of the size of
T
. -
The distance being in bounds cannot rely on "wrapping around" the address space.
The compiler and standard library generally try to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
ptr_into_vec.offset_from(vec.as_ptr())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Panics
This function panics if T
is a Zero-Sized Type ("ZST").
Examples
Basic usage:
let a = [0; 5]; let ptr1: *const i32 = &a[1]; let ptr2: *const i32 = &a[3]; unsafe { assert_eq!(ptr2.offset_from(ptr1), 2); assert_eq!(ptr1.offset_from(ptr2), -2); assert_eq!(ptr1.offset(2), ptr2); assert_eq!(ptr2.offset(-2), ptr1); }Run
Incorrect usage:
let ptr1 = Box::into_raw(Box::new(0u8)) as *const u8; let ptr2 = Box::into_raw(Box::new(1u8)) as *const u8; let diff = (ptr2 as isize).wrapping_sub(ptr1 as isize); // Make ptr2_other an "alias" of ptr2, but derived from ptr1. let ptr2_other = (ptr1 as *const u8).wrapping_offset(diff); assert_eq!(ptr2 as usize, ptr2_other as usize); // Since ptr2_other and ptr2 are derived from pointers to different objects, // computing their offset is undefined behavior, even though // they point to the same address! unsafe { let zero = ptr2_other.offset_from(ptr2); // Undefined Behavior }Run
pub fn guaranteed_eq(self, other: *const T) -> bool
[src]
Returns whether two pointers are guaranteed to be equal.
At runtime this function behaves like self == other
.
However, in some contexts (e.g., compile-time evaluation),
it is not always possible to determine equality of two pointers, so this function may
spuriously return false
for pointers that later actually turn out to be equal.
But when it returns true
, the pointers are guaranteed to be equal.
This function is the mirror of guaranteed_ne
, but not its inverse. There are pointer
comparisons for which both functions return false
.
The return value may change depending on the compiler version and unsafe code may not
rely on the result of this function for soundness. It is suggested to only use this function
for performance optimizations where spurious false
return values by this function do not
affect the outcome, but just the performance.
The consequences of using this method to make runtime and compile-time code behave
differently have not been explored. This method should not be used to introduce such
differences, and it should also not be stabilized before we have a better understanding
of this issue.
pub fn guaranteed_ne(self, other: *const T) -> bool
[src]
Returns whether two pointers are guaranteed to be unequal.
At runtime this function behaves like self != other
.
However, in some contexts (e.g., compile-time evaluation),
it is not always possible to determine the inequality of two pointers, so this function may
spuriously return false
for pointers that later actually turn out to be unequal.
But when it returns true
, the pointers are guaranteed to be unequal.
This function is the mirror of guaranteed_eq
, but not its inverse. There are pointer
comparisons for which both functions return false
.
The return value may change depending on the compiler version and unsafe code may not
rely on the result of this function for soundness. It is suggested to only use this function
for performance optimizations where spurious false
return values by this function do not
affect the outcome, but just the performance.
The consequences of using this method to make runtime and compile-time code behave
differently have not been explored. This method should not be used to introduce such
differences, and it should also not be stabilized before we have a better understanding
of this issue.
#[must_use = "returns a new pointer rather than modifying its argument"]pub unsafe fn add(self, count: usize) -> *const T
1.26.0[src]
Calculates the offset from a pointer (convenience for .offset(count as isize)
).
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and resulting pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
The computed offset, in bytes, cannot overflow an
isize
. -
The offset being in bounds cannot rely on "wrapping around" the address space. That is, the infinite-precision sum must fit in a
usize
.
The compiler and standard library generally tries to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
vec.as_ptr().add(vec.len())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Consider using wrapping_add
instead if these constraints are
difficult to satisfy. The only advantage of this method is that it
enables more aggressive compiler optimizations.
Examples
Basic usage:
let s: &str = "123"; let ptr: *const u8 = s.as_ptr(); unsafe { println!("{}", *ptr.add(1) as char); println!("{}", *ptr.add(2) as char); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub unsafe fn sub(self, count: usize) -> *const T
1.26.0[src]
Calculates the offset from a pointer (convenience for
.offset((count as isize).wrapping_neg())
).
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and resulting pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
The computed offset cannot exceed
isize::MAX
bytes. -
The offset being in bounds cannot rely on "wrapping around" the address space. That is, the infinite-precision sum must fit in a usize.
The compiler and standard library generally tries to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
vec.as_ptr().add(vec.len()).sub(vec.len())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Consider using wrapping_sub
instead if these constraints are
difficult to satisfy. The only advantage of this method is that it
enables more aggressive compiler optimizations.
Examples
Basic usage:
let s: &str = "123"; unsafe { let end: *const u8 = s.as_ptr().add(3); println!("{}", *end.sub(1) as char); println!("{}", *end.sub(2) as char); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn wrapping_add(self, count: usize) -> *const T
1.26.0[src]
Calculates the offset from a pointer using wrapping arithmetic.
(convenience for .wrapping_offset(count as isize)
)
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
This operation itself is always safe, but using the resulting pointer is not.
The resulting pointer remains attached to the same allocated object that self
points to.
It may not be used to access a different allocated object. Note that in Rust, every
(stack-allocated) variable is considered a separate allocated object.
In other words, let z = x.wrapping_add((y as usize) - (x as usize))
does not make z
the same as y
even if we assume T
has size 1
and there is no overflow: z
is still
attached to the object x
is attached to, and dereferencing it is Undefined Behavior unless
x
and y
point into the same allocated object.
Compared to add
, this method basically delays the requirement of staying within the
same allocated object: add
is immediate Undefined Behavior when crossing object
boundaries; wrapping_add
produces a pointer but still leads to Undefined Behavior if a
pointer is dereferenced when it is out-of-bounds of the object it is attached to. add
can be optimized better and is thus preferable in performance-sensitive code.
The delayed check only considers the value of the pointer that was dereferenced, not the
intermediate values used during the computation of the final result. For example,
x.wrapping_add(o).wrapping_sub(o)
is always the same as x
. In other words, leaving the
allocated object and then re-entering it later is permitted.
If you need to cross object boundaries, cast the pointer to an integer and do the arithmetic there.
Examples
Basic usage:
// Iterate using a raw pointer in increments of two elements let data = [1u8, 2, 3, 4, 5]; let mut ptr: *const u8 = data.as_ptr(); let step = 2; let end_rounded_up = ptr.wrapping_add(6); // This loop prints "1, 3, 5, " while ptr != end_rounded_up { unsafe { print!("{}, ", *ptr); } ptr = ptr.wrapping_add(step); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn wrapping_sub(self, count: usize) -> *const T
1.26.0[src]
Calculates the offset from a pointer using wrapping arithmetic.
(convenience for .wrapping_offset((count as isize).wrapping_neg())
)
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
This operation itself is always safe, but using the resulting pointer is not.
The resulting pointer remains attached to the same allocated object that self
points to.
It may not be used to access a different allocated object. Note that in Rust, every
(stack-allocated) variable is considered a separate allocated object.
In other words, let z = x.wrapping_sub((x as usize) - (y as usize))
does not make z
the same as y
even if we assume T
has size 1
and there is no overflow: z
is still
attached to the object x
is attached to, and dereferencing it is Undefined Behavior unless
x
and y
point into the same allocated object.
Compared to sub
, this method basically delays the requirement of staying within the
same allocated object: sub
is immediate Undefined Behavior when crossing object
boundaries; wrapping_sub
produces a pointer but still leads to Undefined Behavior if a
pointer is dereferenced when it is out-of-bounds of the object it is attached to. sub
can be optimized better and is thus preferable in performance-sensitive code.
The delayed check only considers the value of the pointer that was dereferenced, not the
intermediate values used during the computation of the final result. For example,
x.wrapping_add(o).wrapping_sub(o)
is always the same as x
. In other words, leaving the
allocated object and then re-entering it later is permitted.
If you need to cross object boundaries, cast the pointer to an integer and do the arithmetic there.
Examples
Basic usage:
// Iterate using a raw pointer in increments of two elements (backwards) let data = [1u8, 2, 3, 4, 5]; let mut ptr: *const u8 = data.as_ptr(); let start_rounded_down = ptr.wrapping_sub(2); ptr = ptr.wrapping_add(4); let step = 2; // This loop prints "5, 3, 1, " while ptr != start_rounded_down { unsafe { print!("{}, ", *ptr); } ptr = ptr.wrapping_sub(step); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn set_ptr_value(self, val: *const u8) -> *const T
[src]
Sets the pointer value to ptr
.
In case self
is a (fat) pointer to an unsized type, this operation
will only affect the pointer part, whereas for (thin) pointers to
sized types, this has the same effect as a simple assignment.
The resulting pointer will have provenance of val
, i.e., for a fat
pointer, this operation is semantically the same as creating a new
fat pointer with the data pointer value of val
but the metadata of
self
.
Examples
This function is primarily useful for allowing byte-wise pointer arithmetic on potentially fat pointers:
#![feature(set_ptr_value)] let arr: [i32; 3] = [1, 2, 3]; let mut ptr = &arr[0] as *const dyn Debug; let thin = ptr as *const u8; unsafe { ptr = ptr.set_ptr_value(thin.add(8)); println!("{:?}", &*ptr); // will print "3" }Run
pub unsafe fn read(self) -> T
1.26.0[src]
Reads the value from self
without moving it. This leaves the
memory in self
unchanged.
See ptr::read
for safety concerns and examples.
pub unsafe fn read_volatile(self) -> T
1.26.0[src]
Performs a volatile read of the value from self
without moving it. This
leaves the memory in self
unchanged.
Volatile operations are intended to act on I/O memory, and are guaranteed to not be elided or reordered by the compiler across other volatile operations.
See ptr::read_volatile
for safety concerns and examples.
pub unsafe fn read_unaligned(self) -> T
1.26.0[src]
Reads the value from self
without moving it. This leaves the
memory in self
unchanged.
Unlike read
, the pointer may be unaligned.
See ptr::read_unaligned
for safety concerns and examples.
pub unsafe fn copy_to(self, dest: *mut T, count: usize)
1.26.0[src]
Copies count * size_of<T>
bytes from self
to dest
. The source
and destination may overlap.
NOTE: this has the same argument order as ptr::copy
.
See ptr::copy
for safety concerns and examples.
pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize)
1.26.0[src]
Copies count * size_of<T>
bytes from self
to dest
. The source
and destination may not overlap.
NOTE: this has the same argument order as ptr::copy_nonoverlapping
.
See ptr::copy_nonoverlapping
for safety concerns and examples.
pub fn align_offset(self, align: usize) -> usize
1.36.0[src]
Computes the offset that needs to be applied to the pointer in order to make it aligned to
align
.
If it is not possible to align the pointer, the implementation returns
usize::MAX
. It is permissible for the implementation to always
return usize::MAX
. Only your algorithm's performance can depend
on getting a usable offset here, not its correctness.
The offset is expressed in number of T
elements, and not bytes. The value returned can be
used with the wrapping_add
method.
There are no guarantees whatsoever that offsetting the pointer will not overflow or go beyond the allocation that the pointer points into. It is up to the caller to ensure that the returned offset is correct in all terms other than alignment.
Panics
The function panics if align
is not a power-of-two.
Examples
Accessing adjacent u8
as u16
let x = [5u8, 6u8, 7u8, 8u8, 9u8]; let ptr = x.as_ptr().add(n) as *const u8; let offset = ptr.align_offset(align_of::<u16>()); if offset < x.len() - n - 1 { let u16_ptr = ptr.add(offset) as *const u16; assert_ne!(*u16_ptr, 500); } else { // while the pointer can be aligned via `offset`, it would point // outside the allocation }Run
impl<T> *mut T where
T: ?Sized,
[src]
T: ?Sized,
pub fn is_null(self) -> bool
[src]
Returns true
if the pointer is null.
Note that unsized types have many possible null pointers, as only the raw data pointer is considered, not their length, vtable, etc. Therefore, two pointers that are null may still not compare equal to each other.
Behavior during const evaluation
When this function is used during const evaluation, it may return false
for pointers
that turn out to be null at runtime. Specifically, when a pointer to some memory
is offset beyond its bounds in such a way that the resulting pointer is null,
the function will still return false
. There is no way for CTFE to know
the absolute position of that memory, so we cannot tell if the pointer is
null or not.
Examples
Basic usage:
let mut s = [1, 2, 3]; let ptr: *mut u32 = s.as_mut_ptr(); assert!(!ptr.is_null());Run
pub const fn cast<U>(self) -> *mut U
1.38.0 (const: 1.38.0)[src]
Casts to a pointer of another type.
pub unsafe fn as_ref<'a>(self) -> Option<&'a T>
1.9.0[src]
Returns None
if the pointer is null, or else returns a shared reference to
the value wrapped in Some
. If the value may be uninitialized, as_uninit_ref
must be used instead.
For the mutable counterpart see as_mut
.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be properly aligned.
-
It must be "dereferencable" in the sense defined in the module documentation.
-
The pointer must point to an initialized instance of
T
. -
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get mutated (except insideUnsafeCell
).
This applies even if the result of this method is unused! (The part about being initialized is not yet fully decided, but until it is, the only safe approach is to ensure that they are indeed initialized.)
Examples
Basic usage:
let ptr: *mut u8 = &mut 10u8 as *mut u8; unsafe { if let Some(val_back) = ptr.as_ref() { println!("We got back the value: {}!", val_back); } }Run
Null-unchecked version
If you are sure the pointer can never be null and are looking for some kind of
as_ref_unchecked
that returns the &T
instead of Option<&T>
, know that you can
dereference the pointer directly.
let ptr: *mut u8 = &mut 10u8 as *mut u8; unsafe { let val_back = &*ptr; println!("We got back the value: {}!", val_back); }Run
pub unsafe fn as_uninit_ref<'a>(self) -> Option<&'a MaybeUninit<T>>
[src]
Returns None
if the pointer is null, or else returns a shared reference to
the value wrapped in Some
. In contrast to as_ref
, this does not require
that the value has to be initialized.
For the mutable counterpart see as_uninit_mut
.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be properly aligned.
-
It must be "dereferencable" in the sense defined in the module documentation.
-
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get mutated (except insideUnsafeCell
).
This applies even if the result of this method is unused!
Examples
Basic usage:
#![feature(ptr_as_uninit)] let ptr: *mut u8 = &mut 10u8 as *mut u8; unsafe { if let Some(val_back) = ptr.as_uninit_ref() { println!("We got back the value: {}!", val_back.assume_init()); } }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub unsafe fn offset(self, count: isize) -> *mut T
[src]
Calculates the offset from a pointer.
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and resulting pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
The computed offset, in bytes, cannot overflow an
isize
. -
The offset being in bounds cannot rely on "wrapping around" the address space. That is, the infinite-precision sum, in bytes must fit in a usize.
The compiler and standard library generally tries to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
vec.as_ptr().add(vec.len())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Consider using wrapping_offset
instead if these constraints are
difficult to satisfy. The only advantage of this method is that it
enables more aggressive compiler optimizations.
Examples
Basic usage:
let mut s = [1, 2, 3]; let ptr: *mut u32 = s.as_mut_ptr(); unsafe { println!("{}", *ptr.offset(1)); println!("{}", *ptr.offset(2)); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn wrapping_offset(self, count: isize) -> *mut T
1.16.0[src]
Calculates the offset from a pointer using wrapping arithmetic.
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
This operation itself is always safe, but using the resulting pointer is not.
The resulting pointer remains attached to the same allocated object that self
points to.
It may not be used to access a different allocated object. Note that in Rust, every
(stack-allocated) variable is considered a separate allocated object.
In other words, let z = x.wrapping_offset((y as isize) - (x as isize))
does not make z
the same as y
even if we assume T
has size 1
and there is no overflow: z
is still
attached to the object x
is attached to, and dereferencing it is Undefined Behavior unless
x
and y
point into the same allocated object.
Compared to offset
, this method basically delays the requirement of staying within the
same allocated object: offset
is immediate Undefined Behavior when crossing object
boundaries; wrapping_offset
produces a pointer but still leads to Undefined Behavior if a
pointer is dereferenced when it is out-of-bounds of the object it is attached to. offset
can be optimized better and is thus preferable in performance-sensitive code.
The delayed check only considers the value of the pointer that was dereferenced, not the
intermediate values used during the computation of the final result. For example,
x.wrapping_offset(o).wrapping_offset(o.wrapping_neg())
is always the same as x
. In other
words, leaving the allocated object and then re-entering it later is permitted.
If you need to cross object boundaries, cast the pointer to an integer and do the arithmetic there.
Examples
Basic usage:
// Iterate using a raw pointer in increments of two elements let mut data = [1u8, 2, 3, 4, 5]; let mut ptr: *mut u8 = data.as_mut_ptr(); let step = 2; let end_rounded_up = ptr.wrapping_offset(6); while ptr != end_rounded_up { unsafe { *ptr = 0; } ptr = ptr.wrapping_offset(step); } assert_eq!(&data, &[0, 2, 0, 4, 0]);Run
pub unsafe fn as_mut<'a>(self) -> Option<&'a mut T>
1.9.0[src]
Returns None
if the pointer is null, or else returns a unique reference to
the value wrapped in Some
. If the value may be uninitialized, as_uninit_mut
must be used instead.
For the shared counterpart see as_ref
.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be properly aligned.
-
It must be "dereferencable" in the sense defined in the module documentation.
-
The pointer must point to an initialized instance of
T
. -
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get accessed (read or written) through any other pointer.
This applies even if the result of this method is unused! (The part about being initialized is not yet fully decided, but until it is, the only safe approach is to ensure that they are indeed initialized.)
Examples
Basic usage:
let mut s = [1, 2, 3]; let ptr: *mut u32 = s.as_mut_ptr(); let first_value = unsafe { ptr.as_mut().unwrap() }; *first_value = 4; println!("{:?}", s); // It'll print: "[4, 2, 3]".Run
Null-unchecked version
If you are sure the pointer can never be null and are looking for some kind of
as_mut_unchecked
that returns the &mut T
instead of Option<&mut T>
, know that
you can dereference the pointer directly.
let mut s = [1, 2, 3]; let ptr: *mut u32 = s.as_mut_ptr(); let first_value = unsafe { &mut *ptr }; *first_value = 4; println!("{:?}", s); // It'll print: "[4, 2, 3]".Run
pub unsafe fn as_uninit_mut<'a>(self) -> Option<&'a mut MaybeUninit<T>>
[src]
Returns None
if the pointer is null, or else returns a unique reference to
the value wrapped in Some
. In contrast to as_mut
, this does not require
that the value has to be initialized.
For the shared counterpart see as_uninit_ref
.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be properly aligned.
-
It must be "dereferencable" in the sense defined in the module documentation.
-
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get accessed (read or written) through any other pointer.
This applies even if the result of this method is unused!
pub fn guaranteed_eq(self, other: *mut T) -> bool
[src]
Returns whether two pointers are guaranteed to be equal.
At runtime this function behaves like self == other
.
However, in some contexts (e.g., compile-time evaluation),
it is not always possible to determine equality of two pointers, so this function may
spuriously return false
for pointers that later actually turn out to be equal.
But when it returns true
, the pointers are guaranteed to be equal.
This function is the mirror of guaranteed_ne
, but not its inverse. There are pointer
comparisons for which both functions return false
.
The return value may change depending on the compiler version and unsafe code may not
rely on the result of this function for soundness. It is suggested to only use this function
for performance optimizations where spurious false
return values by this function do not
affect the outcome, but just the performance.
The consequences of using this method to make runtime and compile-time code behave
differently have not been explored. This method should not be used to introduce such
differences, and it should also not be stabilized before we have a better understanding
of this issue.
pub unsafe fn guaranteed_ne(self, other: *mut T) -> bool
[src]
Returns whether two pointers are guaranteed to be unequal.
At runtime this function behaves like self != other
.
However, in some contexts (e.g., compile-time evaluation),
it is not always possible to determine the inequality of two pointers, so this function may
spuriously return false
for pointers that later actually turn out to be unequal.
But when it returns true
, the pointers are guaranteed to be unequal.
This function is the mirror of guaranteed_eq
, but not its inverse. There are pointer
comparisons for which both functions return false
.
The return value may change depending on the compiler version and unsafe code may not
rely on the result of this function for soundness. It is suggested to only use this function
for performance optimizations where spurious false
return values by this function do not
affect the outcome, but just the performance.
The consequences of using this method to make runtime and compile-time code behave
differently have not been explored. This method should not be used to introduce such
differences, and it should also not be stabilized before we have a better understanding
of this issue.
pub unsafe fn offset_from(self, origin: *const T) -> isize
1.47.0[src]
Calculates the distance between two pointers. The returned value is in
units of T: the distance in bytes is divided by mem::size_of::<T>()
.
This function is the inverse of offset
.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and other pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
Both pointers must be derived from a pointer to the same object. (See below for an example.)
-
The distance between the pointers, in bytes, cannot overflow an
isize
. -
The distance between the pointers, in bytes, must be an exact multiple of the size of
T
. -
The distance being in bounds cannot rely on "wrapping around" the address space.
The compiler and standard library generally try to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
ptr_into_vec.offset_from(vec.as_ptr())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Panics
This function panics if T
is a Zero-Sized Type ("ZST").
Examples
Basic usage:
let mut a = [0; 5]; let ptr1: *mut i32 = &mut a[1]; let ptr2: *mut i32 = &mut a[3]; unsafe { assert_eq!(ptr2.offset_from(ptr1), 2); assert_eq!(ptr1.offset_from(ptr2), -2); assert_eq!(ptr1.offset(2), ptr2); assert_eq!(ptr2.offset(-2), ptr1); }Run
Incorrect usage:
let ptr1 = Box::into_raw(Box::new(0u8)); let ptr2 = Box::into_raw(Box::new(1u8)); let diff = (ptr2 as isize).wrapping_sub(ptr1 as isize); // Make ptr2_other an "alias" of ptr2, but derived from ptr1. let ptr2_other = (ptr1 as *mut u8).wrapping_offset(diff); assert_eq!(ptr2 as usize, ptr2_other as usize); // Since ptr2_other and ptr2 are derived from pointers to different objects, // computing their offset is undefined behavior, even though // they point to the same address! unsafe { let zero = ptr2_other.offset_from(ptr2); // Undefined Behavior }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub unsafe fn add(self, count: usize) -> *mut T
1.26.0[src]
Calculates the offset from a pointer (convenience for .offset(count as isize)
).
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and resulting pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
The computed offset, in bytes, cannot overflow an
isize
. -
The offset being in bounds cannot rely on "wrapping around" the address space. That is, the infinite-precision sum must fit in a
usize
.
The compiler and standard library generally tries to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
vec.as_ptr().add(vec.len())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Consider using wrapping_add
instead if these constraints are
difficult to satisfy. The only advantage of this method is that it
enables more aggressive compiler optimizations.
Examples
Basic usage:
let s: &str = "123"; let ptr: *const u8 = s.as_ptr(); unsafe { println!("{}", *ptr.add(1) as char); println!("{}", *ptr.add(2) as char); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub unsafe fn sub(self, count: usize) -> *mut T
1.26.0[src]
Calculates the offset from a pointer (convenience for
.offset((count as isize).wrapping_neg())
).
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
If any of the following conditions are violated, the result is Undefined Behavior:
-
Both the starting and resulting pointer must be either in bounds or one byte past the end of the same allocated object. Note that in Rust, every (stack-allocated) variable is considered a separate allocated object.
-
The computed offset cannot exceed
isize::MAX
bytes. -
The offset being in bounds cannot rely on "wrapping around" the address space. That is, the infinite-precision sum must fit in a usize.
The compiler and standard library generally tries to ensure allocations
never reach a size where an offset is a concern. For instance, Vec
and Box
ensure they never allocate more than isize::MAX
bytes, so
vec.as_ptr().add(vec.len()).sub(vec.len())
is always safe.
Most platforms fundamentally can't even construct such an allocation.
For instance, no known 64-bit platform can ever serve a request
for 263 bytes due to page-table limitations or splitting the address space.
However, some 32-bit and 16-bit platforms may successfully serve a request for
more than isize::MAX
bytes with things like Physical Address
Extension. As such, memory acquired directly from allocators or memory
mapped files may be too large to handle with this function.
Consider using wrapping_sub
instead if these constraints are
difficult to satisfy. The only advantage of this method is that it
enables more aggressive compiler optimizations.
Examples
Basic usage:
let s: &str = "123"; unsafe { let end: *const u8 = s.as_ptr().add(3); println!("{}", *end.sub(1) as char); println!("{}", *end.sub(2) as char); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn wrapping_add(self, count: usize) -> *mut T
1.26.0[src]
Calculates the offset from a pointer using wrapping arithmetic.
(convenience for .wrapping_offset(count as isize)
)
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
This operation itself is always safe, but using the resulting pointer is not.
The resulting pointer remains attached to the same allocated object that self
points to.
It may not be used to access a different allocated object. Note that in Rust, every
(stack-allocated) variable is considered a separate allocated object.
In other words, let z = x.wrapping_add((y as usize) - (x as usize))
does not make z
the same as y
even if we assume T
has size 1
and there is no overflow: z
is still
attached to the object x
is attached to, and dereferencing it is Undefined Behavior unless
x
and y
point into the same allocated object.
Compared to add
, this method basically delays the requirement of staying within the
same allocated object: add
is immediate Undefined Behavior when crossing object
boundaries; wrapping_add
produces a pointer but still leads to Undefined Behavior if a
pointer is dereferenced when it is out-of-bounds of the object it is attached to. add
can be optimized better and is thus preferable in performance-sensitive code.
The delayed check only considers the value of the pointer that was dereferenced, not the
intermediate values used during the computation of the final result. For example,
x.wrapping_add(o).wrapping_sub(o)
is always the same as x
. In other words, leaving the
allocated object and then re-entering it later is permitted.
If you need to cross object boundaries, cast the pointer to an integer and do the arithmetic there.
Examples
Basic usage:
// Iterate using a raw pointer in increments of two elements let data = [1u8, 2, 3, 4, 5]; let mut ptr: *const u8 = data.as_ptr(); let step = 2; let end_rounded_up = ptr.wrapping_add(6); // This loop prints "1, 3, 5, " while ptr != end_rounded_up { unsafe { print!("{}, ", *ptr); } ptr = ptr.wrapping_add(step); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn wrapping_sub(self, count: usize) -> *mut T
1.26.0[src]
Calculates the offset from a pointer using wrapping arithmetic.
(convenience for .wrapping_offset((count as isize).wrapping_neg())
)
count
is in units of T; e.g., a count
of 3 represents a pointer
offset of 3 * size_of::<T>()
bytes.
Safety
This operation itself is always safe, but using the resulting pointer is not.
The resulting pointer remains attached to the same allocated object that self
points to.
It may not be used to access a different allocated object. Note that in Rust, every
(stack-allocated) variable is considered a separate allocated object.
In other words, let z = x.wrapping_sub((x as usize) - (y as usize))
does not make z
the same as y
even if we assume T
has size 1
and there is no overflow: z
is still
attached to the object x
is attached to, and dereferencing it is Undefined Behavior unless
x
and y
point into the same allocated object.
Compared to sub
, this method basically delays the requirement of staying within the
same allocated object: sub
is immediate Undefined Behavior when crossing object
boundaries; wrapping_sub
produces a pointer but still leads to Undefined Behavior if a
pointer is dereferenced when it is out-of-bounds of the object it is attached to. sub
can be optimized better and is thus preferable in performance-sensitive code.
The delayed check only considers the value of the pointer that was dereferenced, not the
intermediate values used during the computation of the final result. For example,
x.wrapping_add(o).wrapping_sub(o)
is always the same as x
. In other words, leaving the
allocated object and then re-entering it later is permitted.
If you need to cross object boundaries, cast the pointer to an integer and do the arithmetic there.
Examples
Basic usage:
// Iterate using a raw pointer in increments of two elements (backwards) let data = [1u8, 2, 3, 4, 5]; let mut ptr: *const u8 = data.as_ptr(); let start_rounded_down = ptr.wrapping_sub(2); ptr = ptr.wrapping_add(4); let step = 2; // This loop prints "5, 3, 1, " while ptr != start_rounded_down { unsafe { print!("{}, ", *ptr); } ptr = ptr.wrapping_sub(step); }Run
#[must_use = "returns a new pointer rather than modifying its argument"]pub fn set_ptr_value(self, val: *mut u8) -> *mut T
[src]
Sets the pointer value to ptr
.
In case self
is a (fat) pointer to an unsized type, this operation
will only affect the pointer part, whereas for (thin) pointers to
sized types, this has the same effect as a simple assignment.
The resulting pointer will have provenance of val
, i.e., for a fat
pointer, this operation is semantically the same as creating a new
fat pointer with the data pointer value of val
but the metadata of
self
.
Examples
This function is primarily useful for allowing byte-wise pointer arithmetic on potentially fat pointers:
#![feature(set_ptr_value)] let mut arr: [i32; 3] = [1, 2, 3]; let mut ptr = &mut arr[0] as *mut dyn Debug; let thin = ptr as *mut u8; unsafe { ptr = ptr.set_ptr_value(thin.add(8)); println!("{:?}", &*ptr); // will print "3" }Run
pub unsafe fn read(self) -> T
1.26.0[src]
Reads the value from self
without moving it. This leaves the
memory in self
unchanged.
See ptr::read
for safety concerns and examples.
pub unsafe fn read_volatile(self) -> T
1.26.0[src]
Performs a volatile read of the value from self
without moving it. This
leaves the memory in self
unchanged.
Volatile operations are intended to act on I/O memory, and are guaranteed to not be elided or reordered by the compiler across other volatile operations.
See ptr::read_volatile
for safety concerns and examples.
pub unsafe fn read_unaligned(self) -> T
1.26.0[src]
Reads the value from self
without moving it. This leaves the
memory in self
unchanged.
Unlike read
, the pointer may be unaligned.
See ptr::read_unaligned
for safety concerns and examples.
pub unsafe fn copy_to(self, dest: *mut T, count: usize)
1.26.0[src]
Copies count * size_of<T>
bytes from self
to dest
. The source
and destination may overlap.
NOTE: this has the same argument order as ptr::copy
.
See ptr::copy
for safety concerns and examples.
pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize)
1.26.0[src]
Copies count * size_of<T>
bytes from self
to dest
. The source
and destination may not overlap.
NOTE: this has the same argument order as ptr::copy_nonoverlapping
.
See ptr::copy_nonoverlapping
for safety concerns and examples.
pub unsafe fn copy_from(self, src: *const T, count: usize)
1.26.0[src]
Copies count * size_of<T>
bytes from src
to self
. The source
and destination may overlap.
NOTE: this has the opposite argument order of ptr::copy
.
See ptr::copy
for safety concerns and examples.
pub unsafe fn copy_from_nonoverlapping(self, src: *const T, count: usize)
1.26.0[src]
Copies count * size_of<T>
bytes from src
to self
. The source
and destination may not overlap.
NOTE: this has the opposite argument order of ptr::copy_nonoverlapping
.
See ptr::copy_nonoverlapping
for safety concerns and examples.
pub unsafe fn drop_in_place(self)
1.26.0[src]
Executes the destructor (if any) of the pointed-to value.
See ptr::drop_in_place
for safety concerns and examples.
pub unsafe fn write(self, val: T)
1.26.0[src]
Overwrites a memory location with the given value without reading or dropping the old value.
See ptr::write
for safety concerns and examples.
pub unsafe fn write_bytes(self, val: u8, count: usize)
1.26.0[src]
Invokes memset on the specified pointer, setting count * size_of::<T>()
bytes of memory starting at self
to val
.
See ptr::write_bytes
for safety concerns and examples.
pub unsafe fn write_volatile(self, val: T)
1.26.0[src]
Performs a volatile write of a memory location with the given value without reading or dropping the old value.
Volatile operations are intended to act on I/O memory, and are guaranteed to not be elided or reordered by the compiler across other volatile operations.
See ptr::write_volatile
for safety concerns and examples.
pub unsafe fn write_unaligned(self, val: T)
1.26.0[src]
Overwrites a memory location with the given value without reading or dropping the old value.
Unlike write
, the pointer may be unaligned.
See ptr::write_unaligned
for safety concerns and examples.
pub unsafe fn replace(self, src: T) -> T
1.26.0[src]
Replaces the value at self
with src
, returning the old
value, without dropping either.
See ptr::replace
for safety concerns and examples.
pub unsafe fn swap(self, with: *mut T)
1.26.0[src]
Swaps the values at two mutable locations of the same type, without
deinitializing either. They may overlap, unlike mem::swap
which is
otherwise equivalent.
See ptr::swap
for safety concerns and examples.
pub fn align_offset(self, align: usize) -> usize
1.36.0[src]
Computes the offset that needs to be applied to the pointer in order to make it aligned to
align
.
If it is not possible to align the pointer, the implementation returns
usize::MAX
. It is permissible for the implementation to always
return usize::MAX
. Only your algorithm's performance can depend
on getting a usable offset here, not its correctness.
The offset is expressed in number of T
elements, and not bytes. The value returned can be
used with the wrapping_add
method.
There are no guarantees whatsoever that offsetting the pointer will not overflow or go beyond the allocation that the pointer points into. It is up to the caller to ensure that the returned offset is correct in all terms other than alignment.
Panics
The function panics if align
is not a power-of-two.
Examples
Accessing adjacent u8
as u16
let x = [5u8, 6u8, 7u8, 8u8, 9u8]; let ptr = x.as_ptr().add(n) as *const u8; let offset = ptr.align_offset(align_of::<u16>()); if offset < x.len() - n - 1 { let u16_ptr = ptr.add(offset) as *const u16; assert_ne!(*u16_ptr, 500); } else { // while the pointer can be aligned via `offset`, it would point // outside the allocation }Run
impl<T> *const [T]
[src]
pub fn len(self) -> usize
[src]
Returns the length of a raw slice.
The returned value is the number of elements, not the number of bytes.
This function is safe, even when the raw slice cannot be cast to a slice reference because the pointer is null or unaligned.
Examples
#![feature(slice_ptr_len)] use std::ptr; let slice: *const [i8] = ptr::slice_from_raw_parts(ptr::null(), 3); assert_eq!(slice.len(), 3);Run
pub fn as_ptr(self) -> *const T
[src]
Returns a raw pointer to the slice's buffer.
This is equivalent to casting self
to *const T
, but more type-safe.
Examples
#![feature(slice_ptr_get)] use std::ptr; let slice: *const [i8] = ptr::slice_from_raw_parts(ptr::null(), 3); assert_eq!(slice.as_ptr(), 0 as *const i8);Run
pub unsafe fn get_unchecked<I>(
self,
index: I
) -> *const <I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,
[src]
self,
index: I
) -> *const <I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,
Returns a raw pointer to an element or subslice, without doing bounds checking.
Calling this method with an out-of-bounds index or when self
is not dereferencable
is undefined behavior even if the resulting pointer is not used.
Examples
#![feature(slice_ptr_get)] let x = &[1, 2, 4] as *const [i32]; unsafe { assert_eq!(x.get_unchecked(1), x.as_ptr().add(1)); }Run
pub unsafe fn as_uninit_slice<'a>(self) -> Option<&'a [MaybeUninit<T>]>
[src]
Returns None
if the pointer is null, or else returns a shared slice to
the value wrapped in Some
. In contrast to as_ref
, this does not require
that the value has to be initialized.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be valid for reads for
ptr.len() * mem::size_of::<T>()
many bytes, and it must be properly aligned. This means in particular:-
The entire memory range of this slice must be contained within a single allocated object! Slices can never span across multiple allocated objects.
-
The pointer must be aligned even for zero-length slices. One reason for this is that enum layout optimizations may rely on references (including slices of any length) being aligned and non-null to distinguish them from other data. You can obtain a pointer that is usable as
data
for zero-length slices usingNonNull::dangling()
.
-
-
The total size
ptr.len() * mem::size_of::<T>()
of the slice must be no larger thanisize::MAX
. See the safety documentation ofpointer::offset
. -
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get mutated (except insideUnsafeCell
).
This applies even if the result of this method is unused!
See also slice::from_raw_parts
.
impl<T> *mut [T]
[src]
pub fn len(self) -> usize
[src]
Returns the length of a raw slice.
The returned value is the number of elements, not the number of bytes.
This function is safe, even when the raw slice cannot be cast to a slice reference because the pointer is null or unaligned.
Examples
#![feature(slice_ptr_len)] use std::ptr; let slice: *mut [i8] = ptr::slice_from_raw_parts_mut(ptr::null_mut(), 3); assert_eq!(slice.len(), 3);Run
pub fn as_mut_ptr(self) -> *mut T
[src]
Returns a raw pointer to the slice's buffer.
This is equivalent to casting self
to *mut T
, but more type-safe.
Examples
#![feature(slice_ptr_get)] use std::ptr; let slice: *mut [i8] = ptr::slice_from_raw_parts_mut(ptr::null_mut(), 3); assert_eq!(slice.as_mut_ptr(), 0 as *mut i8);Run
pub unsafe fn get_unchecked_mut<I>(
self,
index: I
) -> *mut <I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,
[src]
self,
index: I
) -> *mut <I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,
Returns a raw pointer to an element or subslice, without doing bounds checking.
Calling this method with an out-of-bounds index or when self
is not dereferencable
is undefined behavior even if the resulting pointer is not used.
Examples
#![feature(slice_ptr_get)] let x = &mut [1, 2, 4] as *mut [i32]; unsafe { assert_eq!(x.get_unchecked_mut(1), x.as_mut_ptr().add(1)); }Run
pub unsafe fn as_uninit_slice<'a>(self) -> Option<&'a [MaybeUninit<T>]>
[src]
Returns None
if the pointer is null, or else returns a shared slice to
the value wrapped in Some
. In contrast to as_ref
, this does not require
that the value has to be initialized.
For the mutable counterpart see as_uninit_slice_mut
.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be valid for reads for
ptr.len() * mem::size_of::<T>()
many bytes, and it must be properly aligned. This means in particular:-
The entire memory range of this slice must be contained within a single allocated object! Slices can never span across multiple allocated objects.
-
The pointer must be aligned even for zero-length slices. One reason for this is that enum layout optimizations may rely on references (including slices of any length) being aligned and non-null to distinguish them from other data. You can obtain a pointer that is usable as
data
for zero-length slices usingNonNull::dangling()
.
-
-
The total size
ptr.len() * mem::size_of::<T>()
of the slice must be no larger thanisize::MAX
. See the safety documentation ofpointer::offset
. -
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get mutated (except insideUnsafeCell
).
This applies even if the result of this method is unused!
See also slice::from_raw_parts
.
pub unsafe fn as_uninit_slice_mut<'a>(self) -> Option<&'a mut [MaybeUninit<T>]>
[src]
Returns None
if the pointer is null, or else returns a unique slice to
the value wrapped in Some
. In contrast to as_mut
, this does not require
that the value has to be initialized.
For the shared counterpart see as_uninit_slice
.
Safety
When calling this method, you have to ensure that either the pointer is NULL or all of the following is true:
-
The pointer must be valid for reads and writes for
ptr.len() * mem::size_of::<T>()
many bytes, and it must be properly aligned. This means in particular:-
The entire memory range of this slice must be contained within a single allocated object! Slices can never span across multiple allocated objects.
-
The pointer must be aligned even for zero-length slices. One reason for this is that enum layout optimizations may rely on references (including slices of any length) being aligned and non-null to distinguish them from other data. You can obtain a pointer that is usable as
data
for zero-length slices usingNonNull::dangling()
.
-
-
The total size
ptr.len() * mem::size_of::<T>()
of the slice must be no larger thanisize::MAX
. See the safety documentation ofpointer::offset
. -
You must enforce Rust's aliasing rules, since the returned lifetime
'a
is arbitrarily chosen and does not necessarily reflect the actual lifetime of the data. In particular, for the duration of this lifetime, the memory the pointer points to must not get accessed (read or written) through any other pointer.
This applies even if the result of this method is unused!
See also slice::from_raw_parts_mut
.
Trait Implementations
impl<T> Clone for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Clone for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T, U> CoerceUnsized<*const U> for *mut T where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<T, U> CoerceUnsized<*const U> for *const T where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<T, U> CoerceUnsized<*mut U> for *mut T where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<T> Copy for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Copy for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Debug for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Debug for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T, U> DispatchFromDyn<*const U> for *const T where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<T, U> DispatchFromDyn<*mut U> for *mut T where
T: Unsize<U> + ?Sized,
U: ?Sized,
[src]
T: Unsize<U> + ?Sized,
U: ?Sized,
impl<T> Eq for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Eq for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Hash for *const T where
T: ?Sized,
[src]
T: ?Sized,
pub fn hash<H>(&self, state: &mut H) where
H: Hasher,
[src]
H: Hasher,
pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
impl<T> Hash for *mut T where
T: ?Sized,
[src]
T: ?Sized,
pub fn hash<H>(&self, state: &mut H) where
H: Hasher,
[src]
H: Hasher,
pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
impl<T> Ord for *mut T where
T: ?Sized,
[src]
T: ?Sized,
pub fn cmp(&self, other: &*mut T) -> Ordering
[src]
#[must_use]pub fn max(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn min(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self
1.50.0[src]
impl<T> Ord for *const T where
T: ?Sized,
[src]
T: ?Sized,
pub fn cmp(&self, other: &*const T) -> Ordering
[src]
#[must_use]pub fn max(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn min(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self
1.50.0[src]
impl<T> PartialEq<*const T> for *const T where
T: ?Sized,
[src]
T: ?Sized,
pub fn eq(&self, other: &*const T) -> bool
[src]
#[must_use]pub fn ne(&self, other: &Rhs) -> bool
[src]
impl<T> PartialEq<*mut T> for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> PartialOrd<*const T> for *const T where
T: ?Sized,
[src]
T: ?Sized,
pub fn partial_cmp(&self, other: &*const T) -> Option<Ordering>
[src]
pub fn lt(&self, other: &*const T) -> bool
[src]
pub fn le(&self, other: &*const T) -> bool
[src]
pub fn gt(&self, other: &*const T) -> bool
[src]
pub fn ge(&self, other: &*const T) -> bool
[src]
impl<T> PartialOrd<*mut T> for *mut T where
T: ?Sized,
[src]
T: ?Sized,
pub fn partial_cmp(&self, other: &*mut T) -> Option<Ordering>
[src]
pub fn lt(&self, other: &*mut T) -> bool
[src]
pub fn le(&self, other: &*mut T) -> bool
[src]
pub fn gt(&self, other: &*mut T) -> bool
[src]
pub fn ge(&self, other: &*mut T) -> bool
[src]
impl<T> Pointer for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Pointer for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> !Send for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> !Send for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> !Sync for *const T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> !Sync for *mut T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> Unpin for *mut T where
T: ?Sized,
1.38.0[src]
T: ?Sized,
impl<T> Unpin for *const T where
T: ?Sized,
1.38.0[src]
T: ?Sized,
impl<T: RefUnwindSafe + ?Sized> UnwindSafe for *const T
1.9.0[src]
impl<T: RefUnwindSafe + ?Sized> UnwindSafe for *mut T
1.9.0[src]
Auto Trait Implementations
impl<T: ?Sized> RefUnwindSafe for *const T where
T: RefUnwindSafe,
[src]
T: RefUnwindSafe,
impl<T: ?Sized> RefUnwindSafe for *mut T where
T: RefUnwindSafe,
[src]
T: RefUnwindSafe,
impl<T> RefUnwindSafe for *const [T] where
T: RefUnwindSafe,
[src]
T: RefUnwindSafe,
impl<T> RefUnwindSafe for *mut [T] where
T: RefUnwindSafe,
[src]
T: RefUnwindSafe,
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut F
impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> From<T> for T
[src]
impl<T> From<T> for T
[src]
impl<T> From<T> for T
[src]
impl<T> From<T> for T
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
[src]
pub fn clone_into(&self, target: &mut T)
[src]
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
[src]
pub fn clone_into(&self, target: &mut T)
[src]
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
[src]
pub fn clone_into(&self, target: &mut T)
[src]
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
[src]
pub fn clone_into(&self, target: &mut T)
[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,