Eric Blake wrote: > The difference you are running into is the fact that 'int' and 'long int' (or > alternately spelled, 'int' and 'long') are distinct types, even if they both > occupy 32 bits and are both signed.
Right. That was my understanding [*] which is why I assumed the cygwin headers (in their 1.5 incarnation) needed some adjustment. But 1.7 already has the fix, so... [*] "But on cygwin, unsigned long is unsigned, it is an integral type,..." was my counterfactual argument against Dave's assertion that typedef unsigned int u_int16_t __attribute__ ((__mode__ (__HI__))); typedef unsigned short int uint16_t; are somehow obviously identical. (They ARE identical, but it is unobvious). Spellings matter. Except when they don't. >> [Dave's argument elided] >> Your argument seems to imply that there is. I always thought that the >> 'int' was implied when only the size (or signedness) was specified, and >> that the types were exactly identical. No? Reference, please? > How about C99 6.2.5 Types: [snipped] > and 6.7.2 Type specifiers: [snipped] These both agree with my earlier understanding. But then I still don't understand how Dave's "fix" would fix anything: Changing: typedef long int32_t typedef unsigned long uint32_t To: typedef long int int32_t typedef unsigned long int uint32_t (e.g as Dave said, "just add 'int' where it's missing" -- that is, ADD, not replace) is a case of changing the spelling without changing the meaning at all; that change would have zero effect and the definition of uint32_t would STILL be different than u_int32_t, an "unsigned int". Right? > And with this knowledge, you then get to play with what gcc means by > >>> typedef unsigned int u_int16_t __attribute__ ((__mode__ (__HI__))); >>> typedef unsigned short int uint16_t; > > They are based on two different base types (unsigned int vs. unsigned short > int), but the presence of __attribute__ means that you are outside the realm > of > C99, so it is up to the compiler whether u_int16_t is effectively the same > class as 'unsigned short int' or whether it behaves more like an 'unsigned > int' > truncated to 16 bits. And that's where I don't know the right answer. Yep. Deep dark compiler magic. -- Chuck -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
