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我修改，並從該post測試程序：如何理解pthread_cancel導致「終止調用沒有活動異常」？
#include <unistd.h>
#include <pthread.h>
#include <iostream>
using namespace std;
struct Sleepy
{
~Sleepy()
{
cerr<<"...zZzZz..."<<endl;
sleep(999);
}
};
void* sleepyThread(void*)
{
Sleepy f;
cerr<<"Fall asleep...\n";
}
int main()
{
pthread_t thread;
int id=pthread_create(&thread,NULL,&sleepyThread,NULL);
sleep(1); //Give the new thread time to get to the sleeping part...
cerr<<"lets try to cancel it..."<<endl;
pthread_cancel(thread);
pthread_join(thread,NULL);
cerr<<"All is done now..."<<endl;
}
運行它會導致核心轉儲：
......
terminate called without an active exception
Aborted (core dumped)
的堆棧跟蹤是這樣的：
(gdb) bt
#0 0x00007f30325528c0 in raise() from /usr/lib/libc.so.6
#1 0x00007f3032553f72 in abort() from /usr/lib/libc.so.6
#2 0x00007f3032e80035 in __gnu_cxx::__verbose_terminate_handler()
at /build/gcc/src/gcc/libstdc++-v3/libsupc++/vterminate.cc:95
#3 0x00007f3032e7dc46 in __cxxabiv1::__terminate (handler=<optimized out>)
at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:47
#4 0x00007f3032e7dc91 in std::terminate() at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_terminate.cc:57
#5 0x00007f3032e7d7e0 in __cxxabiv1::__gxx_personality_v0 (version=<optimized out>, actions=<optimized out>,
exception_class=0, ue_header=<optimized out>, context=<optimized out>)
at /build/gcc/src/gcc/libstdc++-v3/libsupc++/eh_personality.cc:670
#6 0x00007f30328d4fb5 in _Unwind_ForcedUnwind_Phase2 ([email protected]=0x7f303251ed70,
[email protected]=0x7f303251d750) at /build/gcc/src/gcc/libgcc/unwind.inc:175
#7 0x00007f30328d5575 in _Unwind_ForcedUnwind (exc=0x7f303251ed70, stop=0x7f30331861b0 <unwind_stop>,
stop_argument=<optimized out>) at /build/gcc/src/gcc/libgcc/unwind.inc:207
#8 0x00007f3033186351 in __pthread_unwind() from /usr/lib/libpthread.so.0
#9 0x00007f303317b7d2 in sigcancel_handler() from /usr/lib/libpthread.so.0
#10 <signal handler called>
#11 0x00007f30325dabcd in nanosleep() from /usr/lib/libc.so.6
#12 0x00007f30325dab0a in sleep() from /usr/lib/libc.so.6
#13 0x0000560ce9b04d92 in Sleepy::~Sleepy (this=0x7f303251dee7, __in_chrg=<optimized out>) at sleepy.cpp:10
#14 0x0000560ce9b04bf5 in sleepyThread() at sleepy.cpp:16
#15 0x00007f303317d049 in start_thread() from /usr/lib/libpthread.so.0
#16 0x00007f303260cf0f in clone() from /usr/lib/libc.so.6
我可以」完全理解post中寫的原因。根據我的理解，應該是在__pthread_unwind()這會導致stack unwinding會使本地變量Sleepy f回收，並且這會觸發Sleepy f的析構函數再次被調用。這似乎不合理。
我的理解是否正確？誰能給出更詳細的解釋？
從鏈接的文章：「我們都知道，我們不應該扔裏面析構函數例外，因爲析構函數很可能在處理異常時調用，2個例外在同一時間被稱爲導致C++運行時中止「，」和析構函數內部的睡眠函數是一個取消點，並且當調用pthread_cancel時，實際發生的是拋出匿名異常來執行堆棧解除。我認爲這很清楚。 –