Difference between revisions of "cpp/memory/new/bad alloc"
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{{cpp/title|bad_alloc}} | {{cpp/title|bad_alloc}} | ||
| − | {{cpp/memory/new/ | + | {{cpp/memory/new/navbar}} |
| − | {{ | + | {{dcl begin}} |
| − | {{ | + | {{dcl header|new}} |
| − | {{ | + | {{dcl|1= |
| − | class bad_alloc | + | class bad_alloc; |
}} | }} | ||
| − | {{ | + | {{dcl end}} |
{{tt|std::bad_alloc}} is the type of the object thrown as exceptions by the {{rlp|operator_new|allocation functions}} to report failure to allocate storage. | {{tt|std::bad_alloc}} is the type of the object thrown as exceptions by the {{rlp|operator_new|allocation functions}} to report failure to allocate storage. | ||
| + | |||
| + | {{inheritance diagram/std-bad_alloc}} | ||
===Member functions=== | ===Member functions=== | ||
| − | {{ | + | {{cpp/error/exception/member of derived|bad_alloc}} |
| − | + | ||
| − | + | ||
| − | + | ||
| − | + | ||
| − | {{cpp/error | + | {{cpp/error/exception/inherit}} |
===Example=== | ===Example=== | ||
| − | {{example | + | {{example |
| − | + | |code= | |
| − | + | ||
#include <iostream> | #include <iostream> | ||
#include <new> | #include <new> | ||
| Line 28: | Line 25: | ||
int main() | int main() | ||
{ | { | ||
| − | try { | + | try |
| − | while(true) { | + | { |
| + | while (true) | ||
| + | { | ||
new int[100000000ul]; | new int[100000000ul]; | ||
} | } | ||
| − | } catch(const std::bad_alloc& e) { | + | } |
| + | catch (const std::bad_alloc& e) | ||
| + | { | ||
std::cout << "Allocation failed: " << e.what() << '\n'; | std::cout << "Allocation failed: " << e.what() << '\n'; | ||
} | } | ||
} | } | ||
| − | + | |p=true | |
| + | |output= | ||
Allocation failed: std::bad_alloc | Allocation failed: std::bad_alloc | ||
}} | }} | ||
===See also=== | ===See also=== | ||
| − | {{ | + | {{dsc begin}} |
| − | {{ | + | {{dsc inc|cpp/memory/new/dsc operator_new}} |
| − | {{ | + | {{dsc end}} |
| + | |||
| + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||
Latest revision as of 09:07, 14 June 2023
| Defined in header <new>
|
||
| class bad_alloc; |
||
std::bad_alloc is the type of the object thrown as exceptions by the allocation functions to report failure to allocate storage.
Inheritance diagram
Contents |
[edit] Member functions
| (constructor) |
constructs a new bad_alloc object (public member function) |
| operator= |
replaces the bad_alloc object (public member function) |
| what |
returns the explanatory string (public member function) |
std::bad_alloc::bad_alloc
| (1) | ||
bad_alloc() throw(); |
(until C++11) | |
| bad_alloc() noexcept; |
(since C++11) | |
| (2) | ||
bad_alloc( const bad_alloc& other ) throw(); |
(until C++11) | |
| bad_alloc( const bad_alloc& other ) noexcept; |
(since C++11) | |
Constructs a new bad_alloc object with an implementation-defined null-terminated byte string which is accessible through what().
1) Default constructor.
2) Copy constructor. If *this and other both have dynamic type
std::bad_alloc then std::strcmp(what(), other.what()) == 0.(since C++11)Parameters
| other | - | another exception object to copy |
std::bad_alloc::operator=
bad_alloc& operator=( const bad_alloc& other ) throw(); |
(until C++11) | |
| bad_alloc& operator=( const bad_alloc& other ) noexcept; |
(since C++11) | |
Assigns the contents with those of other. If *this and other both have dynamic type std::bad_alloc then std::strcmp(what(), other.what()) == 0 after assignment.(since C++11)
Parameters
| other | - | another exception object to assign with |
Return value
*this
std::bad_alloc::what
virtual const char* what() const throw(); |
(until C++11) | |
| virtual const char* what() const noexcept; |
(since C++11) | |
Returns the explanatory string.
Parameters
(none)
Return value
Pointer to a null-terminated string with explanatory information. The string is suitable for conversion and display as a std::wstring. The pointer is guaranteed to be valid at least until the exception object from which it is obtained is destroyed, or until a non-const member function (e.g. copy assignment operator) on the exception object is called.
Notes
Implementations are allowed but not required to override what().
Inherited from std::exception
Member functions
| [virtual] |
destroys the exception object (virtual public member function of std::exception)
|
| [virtual] |
returns an explanatory string (virtual public member function of std::exception)
|
[edit] Example
Run this code
#include <iostream> #include <new> int main() { try { while (true) { new int[100000000ul]; } } catch (const std::bad_alloc& e) { std::cout << "Allocation failed: " << e.what() << '\n'; } }
Possible output:
Allocation failed: std::bad_alloc
[edit] See also
| allocation functions (function) |
