Function tract_get_last_error 

pub unsafe extern "C" fn tract_get_last_error() -> *const c_char

Retrieve the last error that happened in this thread. A function encountered an error if its return type is of type TRACT_RESULT and it returned TRACT_RESULT_KO.

Return value

It returns a pointer to a null-terminated UTF-8 string that will contain the error description. Rust side keeps ownership of the buffer. It will be valid as long as no other tract calls is performed by the thread. If no error occured, null is returned.