And, before you mention it, use clang to avoid getting the page long templates related errors.

Type-generic data containers can still be implemented with void pointers and very little runtime overhead, for example: http://lxr.nginx.org/source/src/core/ngx_array.h

I am working in DSP project which was started with typical C++ OO BS, finally with ended up with C compiled as C++ + some simple templates for cases as above.

    int maxi(int, int);
    double: maxd(double, double);
    ...
    #define max(x) _Generic((x), int: maxi, double: maxd, ...default: maxi)

How is it template 'nonsense', when those templates do exactly that?

    #define MAX(a,b) ({ \
        typeof (a) _a = (a); \
        typeof (b) _b = (b); \
        _a > _b ? _a : _b; \
    })

    auto max = [](auto a, auto b) { 
        return (a > b) ? a : b;
    };

    max (3.1415, 42); // returns double
    max (42ul, 78u); // returns unsigned long
    max (17, 16); // returns int