Unless and Until

When adapting code from a program I managed to stumble upon this construct in C:

until( (dh > h) || ((dh == h) && (dl > l)) ) {
 // Code here
}

Apparently it uses macros like these to create that new construct, which exists, by the way, in Ruby and Visual Basic:

#define unless(x)       if(!(x))
#define until(x)        while(!(x))

It's just another case where macros come to the rescue when a need to extend the C programming language arises.