On Mon, Jul 20, 2009 at 1:20 AM, Bernhard 'Gustl' Bauer <[email protected]>wrote:
> Hi,
>
> I just had a look at the define of LWIP_DEBUGF. I wonder whats the use of
> the do {} while(0) statement. Its contens is executed one time, so the loop
> can be omitted, isn't it?
>
> Gustl
>
> #define LWIP_DEBUGF(debug,x) do { \
> if ( \
> ((debug) & LWIP_DBG_ON) && \
> ((debug) & LWIP_DBG_TYPES_ON) && \
> ((s16_t)((debug) & LWIP_DBG_MASK_LEVEL) >= LWIP_DBG_MIN_LEVEL)) { \
> LWIP_PLATFORM_DIAG(x); \
> if ((debug) & LWIP_DBG_HALT) { \
> while(1); \
> } \
> } \
> } while(0)
>
In order to insert all those lines in a #define you have to start it with
something "do{" uses the least chars, and the compiler probably edits it
out.
In a non-debug scenario the line would just be:
#define LWIP_DEBUGF(debug,x)
Enjoy,
*E
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