python - SWIG call function pointers stored within struct -

i have struct follows:

struct power_model {     int64_t (*estimate_energy)(statistics *stats, statistics *scaled_stats, parameters *from, parameters *to, energy_container *energy_container);     int64_t (*estimate_performance)(statistics *stats, parameters *params);     uint32_t (*freq_to_volt)(uint32_t freq); }; 

there multiple power models code contains. wrap these models swig , expose them python can run unit tests.

while swig documentation talks exposing function pointers, not talk function pointers contained within structs. tried encapsulate calls in interface file

%{ #include "models.h" %}  %include "models.h"  %extend power_model {   %pythoncallback;   int64_t (*estimate_energy)(statistics *stats, statistics *scaled_stats, parameters *from, parameters *to, energy_container *energy_container);   int64_t (*estimate_performance)(statistics *stats, parameters *params);   uint32_t (*freq_to_volt)(uint32_t freq);   %nopythoncallback; } 

i tried prefixing field names %constant.

with these approaches, end same error:

in [3]: model.estimate_energy() --------------------------------------------------------------------------- typeerror                                 traceback (most recent call last) <ipython-input-3-b2e3ace2fc9b> in <module>() ----> 1 model.estimate_energy()  typeerror: 'swigpyobject' object not callable 

how can call underlying functions referenced function pointers contained within struct power_model?

edit: elaborate on setup, sources of 2 additional files better explain setup i'm trying achieve power_model interface.

nexus5.c

static int64_t estimate_energy(statistics *stats, statistics *scaled_stats, parameters *from, parameters *to, energy_container *energy) {     ... } static int64_t estimate_performance(statistics *stats, parameters *params) {     ... } static uint32_t freq_to_volt(uint32_t freq) {     ... }  struct power_model nexus5_power_model = {      .estimate_energy = estimate_energy,      .estimate_performance = estimate_performance,      .freq_to_volt = freq_to_volt, }; 

galaxy_s.c

static int64_t estimate_energy(statistics *stats, statistics *scaled_stats, parameters *from, parameters *to, energy_container *energy) {     ... } static int64_t estimate_performance(statistics *stats, parameters *params) {     ... } static uint32_t freq_to_volt(uint32_t freq) {     ... }  struct power_model galaxy_s_power_model = {      .estimate_energy = estimate_energy,      .estimate_performance = estimate_performance,      .freq_to_volt = freq_to_volt, }; 

this works me. solution 5 preferred one.

test.i

%module test  %{ #include "test.h" %}  // solution 5 (right one) %pythoncallback; double f5(double); %nopythoncallback; %ignore f5;  %include "test.h"     

test.h

typedef double (*fptr_t)(double);  // solution 5 double f5(double x) {   return x*x; }  typedef struct bla {   fptr_t f; } bla; 

from within python

import test s = test.bla # assign function pointer s.f = test.f5 # execute s.f(2) 

f function taking function pointer argument