Loop until condition is true

[Grant Edwards]

On 2005-06-18, Peter Otten <__peter__ at web.de> wrote:

>> If you look at C code, at least in my experience the
>> "until" loop is quite rarely used.  (I don't see it once in the source
>> to Python 2.4, for example.)
>
> Long time no C? 
>
> 'until' in C is actually 
>
> do 
>     statement
> while (expression);
>
> I found 136 occurrences of "do {" versus 754 of "while (" and 1224 of "for
> (" in the Python 2.4 source, so using these rough estimates do-while still
> qualifies as "rarely used".

AFAICT, the main use for do/while in C is when you want to
define a block of code with local variables as a macro:

#define DoSomething(foo) \
 do \
   { \
   int i; \
    /* do something with foo and i */ \
   } while (0)

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