Carlo Marcelo Arenas Belón <carenas@xxxxxxxxx> writes: > 0620b39b3b ("compat: add a mkstemps() compatibility function", 2009-05-31) > included a function based on code from libiberty which would result in > undefined behaviour in platforms where timeval's tv_usec is a 32-bit signed > type as shown by: > > wrapper.c:505:31: runtime error: left shift of 594546 by 16 places cannot be represented in type '__darwin_suseconds_t' (aka 'int') I had to scratch my head wondering what an UB was (spell it out as "undefined behaviour" if that is what you wanted to say). > interestingly the version of this code from gcc never had this bug and the > code had a cast that would had prevented the issue (at least in 64-bit > platforms) but was misapplied. > > change the cast to uint64_t so it also works in 32-bit platforms. Yup, regardless of the platform, that's the "right" type to use, certainly more correct than "size_t", as value is declared to be u64 in this function. > gettimeofday(&tv, NULL); > - value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid(); > + value = ((uint64_t)tv.tv_usec << 16) ^ tv.tv_sec ^ getpid(); > filename_template = &pattern[len - 6 - suffix_len]; > for (count = 0; count < TMP_MAX; ++count) { > uint64_t v = value; Thanks.