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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting load by thread 3 at 0x05134160 size 8
==10635== at 0x4EDE907: std::string::_M_mutate(unsigned long,
unsigned long, unsigned long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBC32: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting load by thread 3 at 0x05134170 size 4
==10635== at 0x4EDE9B0: std::string::_M_mutate(unsigned long,
unsigned long, unsigned long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBC32: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting store by thread 3 at 0x05134170 size 4
==10635== at 0x4EDE97D: std::string::_M_mutate(unsigned long,
unsigned long, unsigned long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBC32: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting store by thread 3 at 0x05134160 size 8
==10635== at 0x4EDE984: std::string::_M_mutate(unsigned long,
unsigned long, unsigned long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBC32: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting store by thread 3 at 0x05134178 size 1
==10635== at 0x4EDE987: std::string::_M_mutate(unsigned long,
unsigned long, unsigned long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBC32: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting load by thread 3 at 0x05134160 size 8
==10635== at 0x4EDE3F5: std::string::append(char const*, unsigned
long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBCF1: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting load by thread 3 at 0x05134160 size 8
==10635== at 0x4EDE1CE: std::string::reserve(unsigned long) (in
/usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EDE437: std::string::append(char const*, unsigned
long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBCF1: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting load by thread 3 at 0x05134160 size 8
==10635== at 0x4EDD6A9:
std::string::_Rep::_M_clone(std::allocator<char> const&, unsigned
long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EDE1EB: std::string::reserve(unsigned long) (in
/usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EDE437: std::string::append(char const*, unsigned
long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBCF1: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635== Conflicting load by thread 3 at 0x05134160 size 8
==10635== at 0x4EDD6BB:
std::string::_Rep::_M_clone(std::allocator<char> const&, unsigned
long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EDE1EB: std::string::reserve(unsigned long) (in
/usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EDE437: std::string::append(char const*, unsigned
long) (in /usr/lib/libstdc++.so.6.0.13)
==10635== by 0x4EBBCF1: 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)
==10635== Allocation context: BSS section of /usr/lib/libstdc++.so.6.0.13
==10635== Other segment start (thread 2)
==10635== (thread finished, call stack no longer available)
==10635== Other segment end (thread 2)
==10635== (thread finished, call stack no longer available)
==10635==
==10635==
==10635== For counts of detected and suppressed errors, rerun with: -v
==10635== ERROR SUMMARY: 10 errors from 10 contexts (suppressed: 39 from 33)
------------------------------------------------------------------------------
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