A filter primitive that translates between single-precision
    floating-point numbers and their external representations.

    This routine is implemented by two XDR routines:
    xdr_       Converts VAX F-format floating-point numbers.
    float_F
    xdr_       Converts IEEE T-format floating-point numbers.
    float_S

    You can reference these routines explicitly or you can use
    compiler settings to control which routine is used when you
    reference the xdr_float routine.