C++ In a Nutshell

Name

realloc function — Reallocates memory

Synopsis

void* realloc(void* ptr, size_t size)

The realloc function changes the size of the allocated memory that ptr points to. The new size is size bytes. The return value is a pointer to the newly resized memory block, which might be at a different address than the original block. The pointer is suitably aligned for any type.

The contents of the original memory are preserved, up to the smaller of the new and old sizes. If the new size is larger than the old size, the extra memory above the old size is uninitialized.

The memory might be copied, so you can store only POD values in the memory that you reallocate with realloc.

If ptr is null, realloc behaves just like malloc(size). If size is 0, realloc is like free and frees ptr.

If there is insufficient memory to fulfill the request, the original memory is untouched, and a null pointer is returned.

See Also

calloc function, free function, malloc function, Chapter 6