std::malloc - cppreference.com (original) (raw)
Allocates size bytes of uninitialized storage.
If allocation succeeds, returns a pointer to the lowest (first) byte in the allocated memory block that is suitably aligned for any scalar type (at least as strictly as std::max_align_t) (implicitly creating objects in the destination area).
If size is zero, the behavior is implementation defined (null pointer may be returned, or some non-null pointer may be returned that may not be used to access storage, but has to be passed to std::free).
[edit] Parameters
| size | - | number of bytes to allocate |
|---|
[edit] Return value
On success, returns the pointer to the beginning of newly allocated memory. To avoid a memory leak, the returned pointer must be deallocated with std::free() or std::realloc().
On failure, returns a null pointer.
[edit] Notes
This function does not call constructors or initialize memory in any way. There are no ready-to-use smart pointers that could guarantee that the matching deallocation function is called. The preferred method of memory allocation in C++ is using RAII-ready functions std::make_unique, std::make_shared, container constructors, etc, and, in low-level library code, new-expression.
For loading a large file, file mapping via OS-specific functions, e.g. mmap on POSIX or CreateFileMapping(A/W) along with MapViewOfFile on Windows, is preferable to allocating a buffer for file reading.
[edit] Example
Output:
p[0] == aaaaa p[1] == bbbbb p[2] == ccccc p[3] == ddddd