How to call esp-idf mcpwm capture api from non-std ?

[vortex314]

I'm using the mcpwm esp-hal for driving a DC motor.

I would like to use the capture module also to measure the rpm's of the motor. As the capture features are not yet implemented in Rust, it's not directlly possible to work with that. I would much regret to go back to C/C++ because of this limitation.

I thought about using the extern "C" calls to call for functions like : mcpwm_new_capture_timer .

However even simple functions like extern "C" esp_get_free_heap_size' lead to : undefined reference to `esp_get_free_heap_size'

How can I proceed for using the capture modules ? Or linking these functions ?