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std::current_exception

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Revision as of 15:55, 2 November 2012 by P12bot (Talk | contribs)

 
 
 
 
Defined in header <exception>
std::exception_ptr current_exception()
(since C++11)

If called during exception handling (typically, in a catch clause), captures the current exception object and creates an std::exception_ptr that holds a reference to that exception object, or to a copy of that exception object (it is implementation-defined if a copy is made)

If the implementation of this function requires a call to new and the call fails, the returned pointer will hold a reference to an instance of std::bad_alloc

If the implementation of this function requires to copy the captured exception object and its copy constructor throws an exception, the returned pointer will hold a reference to the exception thrown. If the copy constructor of the thrown exception object also throws, the returned pointer may hold a reference to an instance of std::bad_exception to break the endless loop.

If the function is called when no exception is being handled, an empty std::exception_ptr is returned.

Contents

Parameters

(none)

Return value

An instance of std::exception_ptr holding a reference to the exception object, or a copy of the exception object, or to an instance of std::bad_alloc or to an instance of std::bad_exception.

Exceptions

noexcept specification:  
noexcept
  

Example

#include <iostream>
#include <string>
#include <exception>
#include <stdexcept>
 
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 {
        std::string().at(1); // this generates an 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

Output:

Caught exception "basic_string::at"

See also

Template:cpp/error/dcl list exception ptrTemplate:cpp/error/dcl list rethrow exceptionTemplate:cpp/error/dcl list make exception ptr