On Mon, Jul 20, 2009 at 1:20 AM, Bernhard 'Gustl' Bauer
<address@hidden <mailto:address@hidden>> 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)