Re: [Libguestfs] [PATCH nbdkit 1/3] common: isaligned: Use uint64_t instead of unsigned int.

On Mon, Sep 17, 2018 at 08:55:06PM +0100, Richard W.M. Jones wrote: > On Mon, Sep 17, 2018 at 10:00:30PM +0300, Nir Soffer wrote: > > On Mon, Sep 17, 2018 at 6:03 PM Richard W.M. Jones <rjones(a)redhat.com&gt; > > wrote: > > > > > This should have no effect. However it's probably better to pass the > > > full type explicitly rather than using an implicit truncation. > > > > > > > Why is it better? OK I'll give one (somewhat contrived) example where it might be better not to rely on implicit truncation of parameters: (1) User is compiling on a 32 bit architecture. (2) They have turned off or are ignoring compiler warnings. (3) The code has forgotten to #include "isaligned.h" (either our code omits this, which is unlikely, or the user is developing a new plugin using the same framework). In this case the uint64_t would be passed as a 64 bit value (eg. in two registers, or as a 64 bit stack entry), and thus the receiving function would get the wrong parameters.