On Thu, May 27, 2010 at 4:29 AM, Jorge Moraleda
<jorge.moral...@gmail.com> wrote:
>
> Dear all,
>
> Am I doing something wrong, or is is there a race condition somewhere
> in std::istringstream and/or std::getline?
>
> (Bart, Konstantin, this ended up being the error that I've been trying
> to track down for a while and that I thought --erroneously-- was
> caused by std::locale)
>
> This program:
>
> /// file: thread.cpp
> #include <pthread.h>
> #include <string>
> #include <sstream>
>
> void *threadEntry(void *threadid)
> {
>
> std::string bar("01\n23");
> std::istringstream content(bar);
>
> std::string line;
> std::getline(content,line);
>
> pthread_exit(NULL);
> }
>
> int main (int argc, char *argv[])
> {
> pthread_t threads[2];
> int rc;
> long t;
>
> std::ostringstream dummy;
> dummy << 0;
> for(t=0; t<2; t++) {
> rc = pthread_create(&threads[t], NULL, threadEntry, (void *)t);
> }
> pthread_exit(NULL);
> }
>
> when compiled using g++ -g -pthread thread.cpp
> and run with valgrind --tool=drd ./a.out
>
> produces the following output:
>
> ==10635== drd, a thread error detector
> ==10635== Copyright (C) 2006-2009, and GNU GPL'd, by Bart Van Assche.
> ==10635== Using Valgrind-3.5.0-Debian and LibVEX; rerun with -h for
> copyright info
> ==10635== Command: ./a.out
> ==10635==
> ==10635== Thread 3:
> ==10635== Conflicting load by thread 3 at 0x05134160 size 8
> ==10635== at 0x4EBBC2A: std::basic_istream<char,
> std::char_traits<char> >& std::getline<char, std::char_traits<char>,
> std::allocator<char> >(std::basic_istream<char, std::char_traits<char>
> >&, std::basic_string<char, std::char_traits<char>,
> std::allocator<char> >&, char) (in /usr/lib/libstdc++.so.6.0.13)
> ==10635== by 0x400D03: threadEntry(void*) (threads2.cpp:12)
> ==10635== by 0x4C32870: vgDrd_thread_wrapper (drd_pthread_intercepts.c:272)
> ==10635== by 0x55E8A03: start_thread (pthread_create.c:300)
> ==10635== by 0x58DD80C: clone (clone.S:112)
> [ ... ]
Strange. I have tried to reproduce this with gcc 4.4.4 (which includes
libstdc++.so.6.0.13), but did not see any race reports.
Does inserting two pthread_join() calls between pthread_create() and
pthread_exit() in main() help ?
Bart.
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