http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57060
Bug #: 57060
Summary: std::this_thread::get_id() == std::thread::id::id()
without -pthread
Classification: Unclassified
Product: gcc
Version: 4.7.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: r...@gcc.gnu.org
#include <thread>
#include <cassert>
int main()
{
std::thread::id me = std::this_thread::get_id();
std::thread::id nobody;
assert( me != nobody );
}
This program should always succeed, but on GNU/Linux when not linking to
libpthread.so the return value of pthread_self() is pthread_t(0) i.e. the same
as the value set by the default-constructor of std::thread::id
One solution would be to use a different value for the default-constructed
value, possibly -1 if that cannot be a value pthread_t value.
We still have the issue I described at
http://gcc.gnu.org/ml/libstdc++/2011-03/msg00068.html regarding using
pthread_equal() on invalid thread IDs, which could be handled by making
operator== check for the invalid value and avoid a call to pthread_equal.
