On 31 October 2011 15:15, Kevin P. Fleming wrote: > On 10/30/2011 01:12 PM, Jon Grant wrote: >> >> Hello >> >> I've uploaded a simple C program which shows my query: >> >> http://pastebin.com/BQmG0m3g >> >> Is there a way for GCC to warn when union size is exceeded by a bit-field? > > The 'union size' is determined from the largest member of the union. Indeed, I don't see how the compiler could know that you didn't mean to make the union larger than the first member. If you want to put checks in for that, use a static assertions of some kind: char static_assert[(sizeof(REG0) == sizeof(REG0.reg8bit))-1];
