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我修改，并从该post测试程序：如何理解pthread_cancel导致“终止调用没有活动异常”？
#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;
}
运行它会导致核心转储：
......
terminate called without an active exception
Aborted (core dumped)
的堆栈跟踪是这样的：
(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中写的原因。根据我的理解，应该是在__pthread_unwind()这会导致stack unwinding会使本地变量Sleepy f回收，并且这会触发Sleepy f的析构函数再次被调用。这似乎不合理。
我的理解是否正确？谁能给出更详细的解释？
从链接的文章：“我们都知道，我们不应该扔里面析构函数例外，因为析构函数很可能在处理异常时调用，2个例外在同一时间被称为导致C++运行时中止“，”和析构函数内部的睡眠函数是一个取消点，并且当调用pthread_cancel时，实际发生的是抛出匿名异常来执行堆栈解除。我认为这很清楚。 –