std::rethrow_exception
(C++17)<exception>
Throws the previously captured exception object referred-to by the exception pointer p, or a copy of that object.
It is unspecified whether a copy is made. If a copy is made, the storage for it is allocated in an unspecified way.
The behavior is undefined if p is null.
Contents
[edit] Parameters
[edit] Exceptions
The exception object referred-to by p if no copy is made.
Otherwise, a copy of such exception object if the implementation successfully copied the exception object.
Otherwise, std::bad_alloc or the exception thrown when copying the exception object, if allocation or copying fails, respectively.
[edit] Notes
Before P1675R2, rethrow_exception was not allowed to copy the exception object, which is unimplementable on some platforms where exception objects are allocated on the stack.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_constexpr_exceptions |
202411L |
(C++26) | constexpr for exception types |
[edit] Example
#include <exception> #include <iostream> #include <stdexcept> #include <string> void handle_eptr(std::exception_ptr eptr) // passing by value is OK { try { if (eptr) std::rethrow_exception(eptr); } catch(const std::exception & e) { std::cout << "Caught exception: '" << e.what() << "'\n"; } } int main() { std::exception_ptr eptr; try { [[maybe_unused]] char ch = std::string ().at(1); // this generates a std::out_of_range } catch(...) { eptr = std::current_exception (); // capture } handle_eptr(eptr); } // destructor for std::out_of_range called here, when the eptr is destructed
Possible output:
Caught exception: 'basic_string::at: __n (which is 1) >= this->size() (which is 0)'