Initializing defined types

[freevryheid]

This library makes heavy use of defined types from db, con, chunks, vectors, etc.

I've always been confused about the need to initialize defined types before using them. I noted that this was required for the duckdb_result type to pass some early tests, but many of the later tests are passing without initializing the types. This may be compiler related too - we've only tested on gfortran. Anyways, something to consider moving forward.

[ludnic]

This comment reminded me that I was looking at setting up a CI action to run the tests, so I went ahead and added it. The test is failing because of the strange behaviour in retrieving the values in the chunks test.

I don't know the answer regarding initialisation. btw, just to clarify do you mean derived types or is defined types something else I don't know about? if so I see the internal c_ptr is always initialised to c_null_ptr so I was assuming that would be enough.

 type, bind(c) :: duckdb_data_chunk
    type(c_ptr) :: dtck = c_null_ptr
  end type

I saw some of the tests rely on passing a null pointer rather than one of the derived types (or C structures), which we can't do in the fortran API. So I was thinking that an uninitialised type would already have that null pointer and be equivalent. For example:

status = duckdb_appender_flush(nullptr);
REQUIRE(status == DuckDBError);

I have implemented as:

type(duckdb_appender) :: a 
status = duckdb_appender_close(a)
call check(error, status == duckdberror)
if (allocated(error)) return 

assuming that the uninitalised appender is equivalent to a nullptr because a%appdr = c_null_ptr. not sure if it makes fully sense tho.

[freevryheid]

My bad - I meant derived type. Yes, it appears that the initialization of the derived type is applied when first defined so that an explicit call as in : chunk = duckdb_data_chunk(), doesn't appear to be necessary. This would only serve to reinitialize an already initialized derived type.

I've never setup CI actions - have you seen this: https://github.com/awvwgk/setup-fortran

[ludnic]

I've never setup CI actions - have you seen this: https://github.com/awvwgk/setup-fortran

yes I have seen it and it's great. Indeed was part to experiment with it that I have done #38