Re: [libvirt] [Qemu-devel] [PATCH v6 2/6] qapi: Introduce add-fd, remove-fd, query-fdsets

On Tue, Aug 7, 2012 at 8:59 PM, Corey Bryant <coreyb(a)linux.vnet.ibm.com&gt; wrote: > > > On 08/07/2012 02:16 PM, Stefan Hajnoczi wrote: >> >> On Fri, Aug 3, 2012 at 6:28 PM, Corey Bryant <coreyb(a)linux.vnet.ibm.com&gt; >> wrote: >>> + snprintf(fd_str, sizeof(fd_str), "%ld", fd); >>> + qerror_report(QERR_FD_NOT_FOUND, fd_str); >> >> >> Why use an fd_str instead of passing an int64_t into the error >> message? This also assumed sizeof(long) == 8, which isn't true on >> 32-bit hosts, so %ld should be %"PRId64". > > > Can I pass an int64_t into the message if it takes a string? > > I thought int64_t was a long long in 32-bit mode, but perhaps that's not > always the case? The PRId64 format specifier macro from the C standard hides this so you can pass int64_t values to printf()-style functions in a portable way. Stefan