#include <iostream>
#include <map>
#include <thread>
#define SIZE 1024
#define AMOUNT 100000
#define THREADS 4
class A
{
private:
char a[SIZE];
};
void test()
{
std::cout << "test start\n";
std::map<int, A*> container;
for(int i=0; i<AMOUNT; i++)
{
A* a = new A();
std::pair<int, A*>p = std::make_pair(i, a);
container.insert(p);
}
std::cout << "test release\n";
for(int i=0; i<AMOUNT; i++)
{
auto iter = container.find(i);
delete iter->second;
container.erase(iter);
}
std::cout << "test end\n";
}
int main()
{
std::thread ts[THREADS];
for(int i=0; i<THREADS; i++)
{
ts[i] = std::thread(test);
}
for(std::thread& x: ts)
{
x.join();
}
return 0;
}
g++ -pthread -o one one.cpp -Wall -std=c++11 -O3ldd one,得到: linux-vdso.so.1 => (0x00007ffebafce000)
libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fb47352a000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fb473313000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fb4730f4000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fb472d2a000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fb472a22000)
/lib64/ld-linux-x86-64.so.2 (0x00005654c5112000)
./one,一切正常。g++ -pthread -o one one.cpp -Wall -std=c++11 -O3 -staticldd one,得到: not a dynamic executable
test start
Segmentation fault (core dumped)
-g重新编译,gdb显示:wang[00:35][~/test]$ gdb one
GNU gdb (Ubuntu 7.10-1ubuntu2) 7.10
Copyright (C) 2015 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-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from one...done.
(gdb) run
Starting program: /home/wang/test/one
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff7ffa700 (LWP 3623)]
test start
[New Thread 0x7ffff77f8700 (LWP 3624)]
test start
[New Thread 0x7ffff6ff7700 (LWP 3625)]
test start
[New Thread 0x7ffff67f6700 (LWP 3626)]
test start
Program received signal SIGSEGV, Segmentation fault.
0x0000000000000000 in ?? ()
(gdb)
boost::thread库( boost 版:1.60),std::thread替换为boost::thread,并建立静态链接,g++ -pthread -o one1 one.cpp -Wall -std=c++11 -O3 -I /opt/boost/include/ -L /opt/boost/lib/ -lboost_system -lboost_thread -static最佳答案
首先,解决方案。这将在这里工作:
更新: Since Ubuntu 18.04,您还需要链接到librt(添加-lrt):
g++ -o one one.cpp -Wall -std=c++11 -O3 -static -lrt -pthread \
-Wl,--whole-archive -lpthread -Wl,--no-whole-archive
g++ -o one one.cpp -Wall -std=c++11 -O3 -static -pthread \
-Wl,--whole-archive -lpthread -Wl,--no-whole-archive
-pthread时,编译器将已经针对pthread进行链接(并且取决于平台,它确实定义了额外的宏,例如-D_REENTRANT,有关更多详细信息,请参见this question)。-pthread暗示-lpthread,为什么在静态链接时需要指定-lpthread? Wl,--whole-archive有什么作用?By default, without any annotation, a symbol in an object file is strong. During linking, a strong symbol can override a weak symbol of the same name. In contrast, two strong symbols that share a name yield a link error during link-time.
ld支持--whole-archive选项。man ld :
--whole-archive:For each archive mentioned on the command line after the --whole-archive option, include every object file in the archive in the link, rather than searching the archive for the required object files. This is normally used to turn an archive file into a shared library, forcing every object to be included in the resulting shared library. This option may be used more than once.
-Wl,--whole-archive:Two notes when using this option from gcc: First, gcc doesn't know about this option, so you have to use -Wl,-whole-archive. Second, don't forget to use -Wl,-no-whole-archive after your list of archives, because gcc will add its own list of archives to your link and you may not want this flag to affect those as well.
--no-whole-archive:Turn off the effect of the --whole-archive option for subsequent archive files.
fputc(conceptionally used by printf )是线程安全的,并且需要进行同步,这非常昂贵。在单线程环境中,您不想支付这些费用。因此,实现可以将同步功能实现为空存根,并将功能声明为弱符号。fputc)和pthreads似乎恰好使用了这一技巧。有关详细信息,请引用此question about the usage of weak symbols in glibc。上面的示例取自this answer。$ nm /usr/lib/libc.a 2>/dev/null | grep pthread_mutex_lock
w __pthread_mutex_lock
... (repeats)
__pthread_mutex_lock作为弱符号。静态链接的pthread库包含它作为强符号:$ nm /usr/lib/libpthread.a 2>/dev/null | grep pthread_mutex_lock
U pthread_mutex_lock
pthread_mutex_lock.o:
00000000000006a0 T __pthread_mutex_lock
00000000000006a0 T pthread_mutex_lock
0000000000000000 t __pthread_mutex_lock_full
ldd输出:$ ldd one
linux-vdso.so.1 (0x00007fff79d6d000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007fcaaeeb3000)
libm.so.6 => /usr/lib/libm.so.6 (0x00007fcaaeb9b000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007fcaae983000)
libpthread.so.0 => /usr/lib/libpthread.so.0 (0x00007fcaae763000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007fcaae3bb000)
/lib64/ld-linux-x86-64.so.2 (0x00007fcaaf23b000)
$ ltrace -C ./one
std::ios_base::Init::Init()(0x563ab8df71b1, 0x7ffdc483cae8, 0x7ffdc483caf8, 160) = 0
__cxa_atexit(0x7fab3023bc20, 0x563ab8df71b1, 0x563ab8df7090, 6) = 0
operator new(unsigned long)(16, 0x7ffdc483cae8, 0x7ffdc483caf8, 192) = 0x563ab918bc20
std::thread::_M_start_thread(std::unique_ptr<std::thread::_State, std::default_delete<std::thread::_State> >, void (*)())(0x7ffdc483c990, 0x7ffdc483c998, 0x7fab2fa52320, 0x7fab2fa43a80) = 0
operator new(unsigned long)(16, 0x7fab2f6a1fb0, 0, 0x800000) = 0x563ab918bd70
std::thread::_M_start_thread(std::unique_ptr<std::thread::_State, std::default_delete<std::thread::_State> >, void (*)())(0x7ffdc483c990, 0x7ffdc483c998, 0x7fab2fa52320, 0x7fab2fa43a80) = 0
operator new(unsigned long)(16, 0x7fab2eea0fb0, 0, 0x800000) = 0x563ab918bec0
std::thread::_M_start_thread(std::unique_ptr<std::thread::_State, std::default_delete<std::thread::_State> >, void (*)())(0x7ffdc483c990, 0x7ffdc483c998, 0x7fab2fa52320, 0x7fab2fa43a80test start
) = 0
operator new(unsigned long)(16, 0x7fab2e69ffb0, 0, 0x800000) = 0x563ab918c010
std::thread::_M_start_thread(std::unique_ptr<std::thread::_State, std::default_delete<std::thread::_State> >, void (*)())(0x7ffdc483c990, 0x7ffdc483c998, 0x7fab2fa52320, 0x7fab2fa43a80test start
test start
) = 0
std::thread::join()(0x7ffdc483c9a0, 0x7fab2de9efb0, 0, 0x800000test start
test release
test release
test release
test release
test end
test end
test end
test end
) = 0
std::thread::join()(0x7ffdc483c9a8, 0x7fab2eea19c0, 0x7fab2f6a2700, 0) = 0
std::thread::join()(0x7ffdc483c9b0, 0x7fab2e6a09c0, 0x7fab2eea1700, 0) = 0
std::thread::join()(0x7ffdc483c9b8, 0x7fab2de9f9c0, 0x7fab2e6a0700, 0) = 0
+++ exited (status 0) +++
std::thread::join,很可能会在内部使用pthread_join。可以在ldd输出中列出的(动态链接的)库中找到该符号,即libstdc++.so.6和libpthread.so.0:$ nm /usr/lib/libstdc++.so.6 | grep pthread_join
w pthread_join
$ nm /usr/lib/libpthread.so.0 | grep pthread_join
0000000000008280 T pthread_join
-Wl,--whole-archive -lpthread -Wl,--no-whole-archive的原因。(Makefile.am)
mytarget_LDADD = -Wl,--whole-archive -lpthread -Wl,--no-whole-archive
(configure.ac)
WL_WHOLE_ARCHIVE_HACK="-Wl,--whole-archive"
WL_NO_WHOLE_ARCHIVE_HACK="-Wl,--no-whole-archive"
AC_SUBST(WL_WHOLE_ARCHIVE_HACK)
AC_SUBST(WL_NO_WHOLE_ARCHIVE_HACK)
(Makefile.am)
mytarget_LDADD = @WL_WHOLE_ARCHIVE_HACK@ -lpthread @WL_NO_WHOLE_ARCHIVE_HACK@
关于c++ - 当g++静态链接pthread时,导致段错误,为什么?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35116327/
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