It looks like any use of std::thread compiled in a program without -pthread (or
probably some specific macro set by -pthread, but hard to say as -pthread isn't
really documented to begin with) will crash on the spot. For instance, this
code:
#include <thread>
void f() {}
int main()
{
std::thread t(f);
t.join();
}
will die unless -pthread is set:
$ g++-4.5-20091112 -std=c++0x -ggdb -O0 fail.cpp -o fail
$ gdb ./fail
GNU gdb 6.8
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu"...
(gdb) run
Starting program: /home/lloyd/fail
Program received signal SIGSEGV, Segmentation fault.
0x00007faf94deb459 in ?? () from /lib64/ld-linux-x86-64.so.2
(gdb) backtrace
#0 0x00007faf94deb459 in ?? () from /lib64/ld-linux-x86-64.so.2
#1 0x00007faf94df14b5 in ?? () from /lib64/ld-linux-x86-64.so.2
#2 0x00007faf94b87a27 in std::thread::_M_start_thread (this=0x7fff9cff8850,
__b=
{<std::__shared_ptr<std::thread::_Impl_base,
(__gnu_cxx::_Lock_policy)2u>> = {_M_ptr = 0x1669030, _M_refcount = {_M_pi =
0x1669010}}, <No data fields>})
at ../../../../gcc-4.5-20091112/libstdc++-v3/src/thread.cc:88
#3 0x0000000000400eed in thread<void (*)()> (this=0x7fff9cff8850, __f=0x400ca4
<f()>)
at
/usr/local/gcc-4.5-20091112/lib/gcc/x86_64-unknown-linux-gnu/4.5.0/../../../../include/c++/4.5.0/typeinfo:121
#4 0x0000000000400cc4 in main ()
(gdb)
Some thoughts:
Perhaps -pthread should be implied by -std=c++0x/-std=gnu++0x? (Except at least
nominally one could use std::thread with DCE or Solaris threads, so is -pthread
right anyway?)
At least an assert() failure or (preferably) a compile-time error would be
nice; I can't imagine a much worst compiler diagnostic than having the program
silently crash with a segmentation fault.
--
Summary: [C++0x] Using std::thread without -pthread causes
immediate crash
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: lloyd at randombit dot net
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42198
