Linked by Amjith Ramanujam on Fri 21st Nov 2008 03:38 UTC
The Linux kernel uses several special capabilities of the GNU Compiler Collection (GCC) suite. These capabilities range from giving you shortcuts and simplifications to providing the compiler with hints for optimization. Discover some of these special GCC features and learn how to use them in the Linux kernel.
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Member since:2005-07-06
Member since:2006-02-23
Could you please explain further. For me the line (void) (&_min1 == &_min2); is still somewhat inexplicable, since it does not seem to do anything other than compare the two pointers of the temporary variables (which are always distinct) and cast the result to void. So it seems to me as an addendum to the macro (they must have first written it without this line) to keep GCC from generating warnings. Why GCC refrains from the warning after this line is not completely clear to me.
Member since:
2006-01-10
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#define min(x, y) ({ \
typeof(x) _min1 = (x); \
typeof(y) _min2 = (y); \
(void) (&_min1 == &_min2); \
_min1 < _min2 ? _min1 : _min2; })
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anyone know what why this line is there:
void) (&_min1 == &_min2);
?