20 Memory management library [mem]

20.2 Memory [memory]

20.2.12 C library memory allocation [c.malloc]

[Note 1:

The header <cstdlib> declares the functions described in this subclause.

— end note]

void* aligned_alloc(size_t alignment, size_t size);
void* calloc(size_t nmemb, size_t size);
void* malloc(size_t size);

Effects: These functions have the semantics specified in the C standard library.

Remarks: These functions do not attempt to allocate storage by calling ::operator new() ([new.delete]).

These functions implicitly create objects ([intro.object]) in the returned region of storage and return a pointer to a suitable created object.

In the case of calloc, the objects are created before the storage is zeroed.

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void* realloc(void* ptr, size_t size);

Preconditions: free(ptr) has well-defined behavior.

Effects: If ptr is not null and size is zero, the behavior is erroneous and the effects are implementation-defined.

Otherwise, this function has the semantics specified in the C standard library.

Remarks: This function does not attempt to allocate storage by calling ::operator new() ([new.delete]).

When a non-null pointer is returned, this function implicitly creates objects ([intro.object]) in the returned region of storage and returns a pointer to a suitable created object.

The objects are created before the storage is copied.

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void free(void* ptr);

Effects: This function has the semantics specified in the C standard library.

Remarks: This function does not attempt to deallocate storage by calling ::operator delete().