Is it possible to use a C++ library from Rust when the library uses templates (generics)?

Question

Is it possible to use a C++ library from Rust when the library (e.g. Boost) uses templates (generics)?

Answer 1

Yes, but it may not be practical.

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The D programming language is one of the very few providing some degree of C++ interoperability; you can read more about it on dlang.

Note the limitation for the template section:

Note that all instantiations used in D code must be provided by linking to C++ object code or shared libraries containing the instantiations.

which essentially means that you must use C++ code to cause the instantiation of the templates with the right types, and then the D compiler will link against those instantiations.

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You could do the same for Rust. Without compiler support, this means mangling the names manually. In the FFI section, you will find the link attribute:

#[link(name = "snappy")]
extern {
    fn snappy_max_compressed_length(source_length: size_t) -> size_t;
}

which tells the compiler which linked library will provide the symbol, you will also support for various calling conventions and the no_mangle attribute.

You may need to apply #[allow(non_snake_case)] as appropriate.

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Servo uses bindgen to generate Rust bindings for C and C++ code; I am unclear on the level of C++ support, and somewhat doubtful that it can handle templates.