std::set_new_handler
| Defined in header <new>
|
||
std::new_handler set_new_handler( std::new_handler new_p ) throw();
|
(until C++11) | |
std::new_handler set_new_handler( std::new_handler new_p ) noexcept;
|
(since C++11) | |
Makes new_p the new global new-handler function and returns the previously installed new-handler.
The new-handler function is the function called by allocation functions whenever a memory allocation attempt fails. Its intended purpose is one of three things:
The default implementation throws std::bad_alloc. The user can install their own new-handler, which may offer behavior different than the default one.
If new-handler returns, the allocation function repeats the previously-failed allocation attempt and calls the new-handler again if the allocation fails again. To end the loop, new-handler may call std::set_new_handler(nullptr): if, after a failed allocation attempt, allocation function finds that std::get_new_handler returns a null pointer value, it will throw std::bad_alloc.
At program startup, new-handler is a null pointer.
|
This function is thread-safe. Every call to |
(since C++11) |
Parameters
| new_p | - | pointer to function of type std::new_handler, or null pointer |
Return value
The previously-installed new handler, or a null pointer value if none was installed.
Example
#include <iostream>
#include <new>
void handler()
{
std::cout << "Memory allocation failed, terminating\n";
std::set_new_handler(nullptr);
}
int main()
{
std::set_new_handler(handler);
try
{
while (true)
{
new int[1000'000'000ul]();
}
}
catch (const std::bad_alloc& e)
{
std::cout << e.what() << '\n';
}
}
Possible output:
Memory allocation failed, terminating
std::bad_alloc