At Wed, 3 Dec 2003 11:18:42 +0000, Steve Harris wrote: > > On Wed, Dec 03, 2003 at 10:41:05 +0000, Mike Rawes wrote: > > -O2 will include the -fstrict-aliasing flag for gcc, so it's turned on here. > > I've no idea what -O6 does (intel compiler, pgcc?). -O3 is the highest in the > > gcc documentation. > > -O6 is historical, I just keep it in cos it doesnt hurt. Interesting that > -O2 turns on strict aliasing... that changes the semantics of ANSI C, > though I've a feeling that C99 might specify strict aliasing.
as far as i understand, there is no strict definition of behavior about type punning. with GCC, you can use a union as a workaround (as found in info), but it's not sure to work with other compilers... Takashi
