std::rethrow_exception

Header: <exception>

Throws the previously captured exception object referred-to by the exception pointer p, or a copy of that object.

# Declarations

[[noreturn]] void rethrow_exception( std::exception_ptr p );

(since C++11) (constexpr since C++26)

# Parameters

# 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.

# 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

# See also