Function alloc 

pub fn alloc(size: usize) -> Result<*mut u8, AllocationError>

• A reasonably safe implementation of alloc.
• Memory allocated by this function must be freed by this crate’s free.
• Caller guarantees free is called before the returned pointer goes out of scope.

Errors

• Err(ArithmeticError) on integer overflow.
• Err(ImproperAlignment) if the global allocator returns a misaligned pointer.
• Err(LayoutError) if [ALIGNMENT] isn’t a power of 2 or the computed size is not aligned.
• Err(OutOfMemory) if alloc() returns a nullptr.