id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
7248	UUID Conditional jump or move depends on uninitialised value(s)	df@…	Andy Tompkins	"The following code produces Valgrind warnings:

Code:
{{{
boost::uuids::uuid uuid = boost::uuids::random_generator()();
}}}
Valgrind:
{{{
==5381== Memcheck, a memory error detector
==5381== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==5381== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info
==5381== Command: ../../bin/test/test_r14p
==5381== 
==5381== Conditional jump or move depends on uninitialised value(s)
==5381==    at 0x40296B: main (mersenne_twister.hpp:177)
==5381==  Uninitialised value was created by a heap allocation
==5381==    at 0x4C2747E: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5381==    by 0x4041AD: boost::uuids::detail::seed_rng::sha1_random_digest_() (seed_rng.hpp:162)
==5381==    by 0x402910: main (seed_rng.hpp:103)
==5381== 
==5381== Conditional jump or move depends on uninitialised value(s)
==5381==    at 0x40298D: main (mersenne_twister.hpp:179)
==5381==  Uninitialised value was created by a heap allocation
==5381==    at 0x4C2747E: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5381==    by 0x4041AD: boost::uuids::detail::seed_rng::sha1_random_digest_() (seed_rng.hpp:162)
==5381==    by 0x402910: main (seed_rng.hpp:103)
==5381== 
==5381== Use of uninitialised value of size 8
==5381==    at 0x54DD208: ??? (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x54E25AA: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_int<unsigned long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x54E27A5: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x54F4FCD: std::ostream& std::ostream::_M_insert<unsigned long>(unsigned long) (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x402CCD: main (ostream:195)
==5381==  Uninitialised value was created by a heap allocation
==5381==    at 0x4C2747E: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5381==    by 0x4041AD: boost::uuids::detail::seed_rng::sha1_random_digest_() (seed_rng.hpp:162)
==5381==    by 0x404BBE: void boost::random::detail::fill_array_int_impl<32, 624ul, boost::uuids::detail::generator_iterator<boost::uuids::detail::seed_rng>, unsigned int>(boost::uuids::detail::generator_iterator<boost::uuids::detail::seed_rng>&, boost::uuids::detail::generator_iterator<boost::uuids::detail::seed_rng>, unsigned int (&) [624ul]) (seed_rng.hpp:103)
==5381==    by 0x40295B: main (seed_impl.hpp:324)
==5381== 
==5381== Conditional jump or move depends on uninitialised value(s)
==5381==    at 0x54DD20E: ??? (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x54E25AA: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_int<unsigned long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x54E27A5: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x54F4FCD: std::ostream& std::ostream::_M_insert<unsigned long>(unsigned long) (in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.4.5/libstdc++.so.6.0.13)
==5381==    by 0x402CCD: main (ostream:195)
==5381==  Uninitialised value was created by a heap allocation
==5381==    at 0x4C2747E: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5381==    by 0x4041AD: boost::uuids::detail::seed_rng::sha1_random_digest_() (seed_rng.hpp:162)
==5381==    by 0x404BBE: void boost::random::detail::fill_array_int_impl<32, 624ul, boost::uuids::detail::generator_iterator<boost::uuids::detail::seed_rng>, unsigned int>(boost::uuids::detail::generator_iterator<boost::uuids::detail::seed_rng>&, boost::uuids::detail::generator_iterator<boost::uuids::detail::seed_rng>, unsigned int (&) [624ul]) (seed_rng.hpp:103)
==5381==    by 0x40295B: main (seed_impl.hpp:324)
==5381== 
c0dbd170-11c6-4877-9180-d26753748484
==5381== 
==5381== HEAP SUMMARY:
==5381==     in use at exit: 0 bytes in 0 blocks
==5381==   total heap usage: 128 allocs, 128 frees, 3,596 bytes allocated
==5381== 
==5381== All heap blocks were freed -- no leaks are possible
==5381== 
==5381== For counts of detected and suppressed errors, rerun with: -v
==5381== ERROR SUMMARY: 48 errors from 4 contexts (suppressed: 6 from 6)
}}}

The following works without any warnings:
{{{
boost::mt19937 ran;
boost::uuids::uuid uuid = boost::uuids::random_generator(ran)();
}}}"	Bugs	closed	Boost 1.66.0	uuid	Boost 1.55.0	Problem	worksforme	uuid, valgrind