memory allocation function
() function is obsoleted by the current
version of malloc(3)
aligns page-sized and larger allocations, and
allocates memory with a given alignment.
() function allocates
bytes aligned on a page boundary. It is
implemented by calling malloc(3)
with a slightly larger request, saving the true beginning of the block
allocated, and returning a properly aligned pointer.
() function returns a pointer to the
allocated space if successful; otherwise a null pointer is returned.
() function appeared in
() function has not been implemented.