Ffi pack: enum values

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1

I must say that the more I use the ffi pack the more impressed I am :slight_smile: It is a great piece of well done software engineering. It is just a joy be able to call C code directly from prolog with just a header and the shared library.

I am having trouble on using enum values.
C declaration like this:

enum window_t
{
	// No window functions
	WIN_NONE,							// Rectangle window (or no window)

	// High-resolution window functions
	WIN_SINE,							// Sine window
	WIN_HAMMING,						// Hamming window
	WIN_BLACKMAN,						// Blackman window

	// Low-resolution window functions
	WIN_BLACKMAN_NUTTALL				// Blackman-Nuttall window
};

bool Filter_Diff_flt32 (flt32_t filter[], size_t size, flt32_t lowfreq, flt32_t highfreq, enum window_t window);

Prolog like this:

:- c_import("#include \"Filter.h\"",                  % ffi:cpp_hook provides -I flag
            [ linasm(lib/'liblinasm.so') ],
	    [
	      'Filter_Diff_flt32'( 
                   *float,     % flt32_t filter[],
				    int,       % size_t  size,
				    float,     % flt32_t lowfreq,
				    float,     % flt32_t highfreq,
				    %int,       % window_t window
				    enum(window_t),       % window_t window
				   [void])      % bool, but we ignore for now until fix
	    ]).

e(F) :-
   filter_diff(_,F,5,0,0.4,'WIN_NONE').

filter_diff(FloatType, Filter, OrderHalf, LowFreq, HighFreq, Window) :-
   Count is 2*OrderHalf+1,
   array(float32, Count, Filter),
   'Filter_Diff_flt32'(Filter, OrderHalf, LowFreq, HighFreq, Window).

array(float32, Count, ArrayPtr)  :-
   var(ArrayPtr), !,
   c_alloc(ArrayPtr, float[Count]).

Error:

ERROR: enum_id `'WIN_NONE'' does not exist in filter:window_t

How can I access the enum value in the call to the C function?

2

For those that stumble upon this thread, this is fixed in the latest version of the ffi pack.

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