Function gmp_mpfr_sys::gmp::set_memory_functions

pub unsafe extern "C" fn set_memory_functions(
    alloc_func_ptr: allocate_function, 
    realloc_func_ptr: reallocate_function, 
    free_func_ptr: free_function
)

See: mp_set_memory_functions

Planned change

In the next major version of the crate (version 2), the arguments will be of types Option<allocate_function>, Option<reallocate_function> and Option<free_function>, since the function types themselves will no longer be Option.