C code
==================

General Structure
-----------------

All C library is intended to be compiled into dynamic link library (
``.so`` for Linux, ``.dylib`` for MacOS and ``.dll`` for Windows),
which implements quantum physics related functions.


Band Structure
-------------------------------

:doc:`file/band_8h` includes interfaces for band structure and
:doc:`file/band_8c` has two implementation of two different bands:
Zinc-blende structure and Wurtzite structure.

``struct BAND`` includes a function pointer for updating parameters
depending on band structure, an int number for the size of the band and
a pointer to a double array for bandgap (at different positions).

Both bands should be regarded as `sub-class` of ``struct BAND``, except
that there's no syntax in C for inheritance. Therefore if new band
structure is to be added, it has to be promised that the first three components
are aligned. At the same time add new interface items in :doc:`../bandpy` .


Memory Management
------------------------

Dynamic memory allocation that happened within C functions will be freed within
the function. Memory space for return values should be provided and managed
by callers. And in our cases, by Python modules.

Memory for band parameters is managed by Python, which promises to call
allocate and free functions in the C library during construction and
destruction.

Users are not expected to use the C code directly.

File List
-----------------------
.. toctree::
   :glob:

   file/*