# std::basic_stacktrace<Allocator>::operator=

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basic_stacktrace& operator=( const basic_stacktrace& other ); | (1) | (since C++23)
basic_stacktrace& operator=( basic_stacktrace&& other ) noexcept(/* see below */); | (2) | (since C++23)

Replaces the contents of the `basic_stacktrace`.

1) Copy assignment operator. Replaces the contents with a copy of the contents of `other`.
If std::allocator_traits<allocator_type>::propagate_on_container_copy_assignment::value is true, the allocator of *this is replaced by a copy of that of `other`. If the allocator of *this after assignment would compare unequal to its old value, the old allocator is used to deallocate the memory, then the new allocator is used to allocate it before copying the entries. Otherwise, the memory owned by *this may be reused when possible.
2) Move assignment operator. Replaces the contents with those of `other` using move semantics (i.e. the data in `other` is moved from `other` into *this). `other` is in a valid but unspecified state afterwards.
If std::allocator_traits<allocator_type>::propagate_on_container_move_assignment::value is true, the allocator of *this is replaced by a copy of that of `other`. If it is false and the allocators of *this and `other` do not compare equal, *this cannot take ownership of the memory owned by `other` and must assign each entries individually, allocating additional memory using its own allocator as needed.

In any case, the stacktrace entries originally belong to *this may be either destroyed or replaced by element-wise assignment.

*this may be set to empty on allocation failure if the implementation strengthens the exception specification.

### Parameters

other | - | another `basic_stacktrace` to use as source

### Return value

*this

### Complexity

1) Linear in the size of `*this` and `other`.
2) Linear in the size of `*this` unless the allocators do not compare equal and do not propagate, in which case linear in the size of `*this` and `other`.

### Exceptions

1) May throw implementation-defined exceptions.
2)
`noexcept` specification:
noexcept(std::allocator_traits<Allocator>::propagate_on_container_move_assignment::value
|| std::allocator_traits<Allocator>::is_always_equal::value)

### Notes

After container move assignment (overload (2)), unless element-wise move assignment is forced by incompatible allocators, references, pointers, and iterators (other than the end iterator) to `other` remain valid, but refer to elements that are now in *this. The current standard makes this guarantee via the blanket statement in [container.rev.reqmts]/17, and a more direct guarantee is under consideration via LWG issue 2321.

### Example

| This section is incomplete Reason: no example

### See also

(constructor) (C++23) | creates a new `basic_stacktrace` (public member function)

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