Difference between revisions of "cpp/memory/c/realloc"
From cppreference.com
(typo) |
m (Shorten template names. Use {{lc}} where appropriate.) |
||
| Line 17: | Line 17: | ||
===Parameters=== | ===Parameters=== | ||
| − | {{ | + | {{par begin}} |
| − | {{ | + | {{par | ptr | pointer to the memory area to be reallocated}} |
| − | {{ | + | {{par | new_size | new size of the array}} |
| − | {{ | + | {{par end}} |
===Return value=== | ===Return value=== | ||
| − | Pointer to the beginning of newly allocated memory or {{ | + | Pointer to the beginning of newly allocated memory or {{lc|NULL}} if error has occurred. The pointer must be deallocated with {{rlpf|free}}. |
===Example=== | ===Example=== | ||
| Line 32: | Line 32: | ||
===See also=== | ===See also=== | ||
| − | {{ | + | {{dsc begin}} |
| − | {{ | + | {{dsc see c | c/memory/realloc}} |
| − | {{ | + | {{dsc end}} |
[[de:cpp/memory/c/realloc]] | [[de:cpp/memory/c/realloc]] | ||
Revision as of 19:13, 31 May 2013
| Defined in header <cstdlib>
|
||
| void* realloc( void* ptr, std::size_t new_size ); |
||
Reallocates the given area of memory. It must be previously allocated by malloc(), calloc() or realloc() and not yet freed with free(), otherwise, the results are undefined.
The reallocation is done by either:
a) expanding or contracting the existing area pointed to by
ptr, if possible. The contents of the area remain unchanged up to the lesser of the new and old sizes. If the area is expanded, the contents of the new part of the array are undefined. b) allocating a new memory block of size
new_size bytes, copying memory area with size equal the lesser of the new and the old sizes, and freeing the old block.If there is not enough memory, the old memory block is not freed and null-pointer is returned.
Contents |
Notes
Because reallocation may involve bytewise copying (regardless of whether it's to expand or to contract), only the objects of Template:concept types are safe to access in the preserved part of the memory block after a call to realloc.
Parameters
| ptr | - | pointer to the memory area to be reallocated |
| new_size | - | new size of the array |
Return value
Pointer to the beginning of newly allocated memory or NULL if error has occurred. The pointer must be deallocated with free().
Example
| This section is incomplete Reason: no example |
See also
| C documentation for realloc
|
