| bcd_var | Function (Macro)

timath.h

#define bcd_var(a) (*(bcd*)&(a))

Converts reference to float object to reference to BCD object.

bcd_var converts the reference to a floating point object x (which must be an lvalue, for example a floating point variable) to the reference to the same object, but interpreted as a bcd structure. bcd_var is similar as float_to_bcd, but returned object is an lvalue, so it may be used in assignments like

    float a;
    ...
    bcd_var(a).exponent = 0x4002;

The drawback of bcd_var (compared with float_to_bcd) is the fact that its argument must be an lvalue, so it can not be a floating point constant or any non-lvalue expression (for example, a result of a function).
Note: I used notation "&bcd_var" and "&x" in the prototype description, although passing by reference and returning results by reference does not exist in ordinary C (only in C++). However, this bcd_var is macro which is implemented on such way that it simulates "passing and returning by reference".