Maybe "not ideomatic" is not quite the right word... They are explicitly making their API more complex in order to support unusual usages. They avoid heap alloc

Maybe "not ideomatic" is not quite the right word... They are explicitly making their API more complex in order to support unusual usages. They avoid heap allocation by making user pre-allocate output buffers. And they even avoid stack allocation by having user provide "void* tmp" argument (see [0]). One can definitely implement such interface in Rust, but I don't think it would be pleasant to use. Having to worry about temp buffer allocation at most calls is not something one wants to do. I am pretty sure that this library is designed to be wrapped by a second layer -- be it in Rust, C++ or even GLib-style C. [0] https://falcon-sign.info/impl/falcon.h.html https://falcon-sign.info/impl/falcon.h.html