PTHREAD_CANCEL_ASYNCHRONOUS
在 C 程序中,一旦从父线程触发 pthread_cancel ,我就会立即取消线程。但它导致整个过程因Segmentation Fault崩溃。子线程的工作是从数据库服务器获取一些数据。我的逻辑是,如果它没有在 10 秒内获取数据,则该线程应该从父线程中被杀死。
我只想杀死子线程,而不是整个过程。
struct str_thrd_data
{
SQLHANDLE hstmt;
int rc;
bool thrd_completed_flag;
};
void * str_in_thread_call(void *in_str_arg)
{
int thrd_rc;
struct str_thrd_data *str_arg;
str_arg = in_str_arg;
thrd_rc = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
if (thrd_rc != 0)
handle_error_en(thrd_rc, "pthread_setcancelstate");
thrd_rc = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
if (thrd_rc != 0)
handle_error_en(thrd_rc, "pthread_setcancelstate");
thrd_rc = pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
if (thrd_rc != 0)
handle_error_en(thrd_rc, "pthread_setcanceltype");
// Code to call SQL Dynamic Query from a Database Server. This takes time more than 10 seconds.
thrd_rc = SQLExecute(hstmt);
printf("\n*********************Normal Thread termination withing timelimit %d\n",str_arg->rc);
str_arg->thrd_completed_flag = true;
}
int main()
{
printf("\nPJH: New THread created.\n");
pthread_attr_t tattr;
pthread_t th;
size_t mysize = 1;
struct str_thrd_data atd;
atd.hstmt = hstmt;
atd.rc= rc;
atd.thrd_completed_flag = false;
thrd_rc = pthread_attr_init(&tattr);
thrd_rc = pthread_attr_setstacksize(&tattr, mysize);
thrd_rc = pthread_create(&th, &tattr, &str_in_thread_call, &atd);
if (thrd_rc != 0)
handle_error_en(thrd_rc, "pthread_create");
// While Loop tp count till 10 seconds.
while(timeout !=0)
{
printf("%d Value of rc=%d\n",timeout, atd.rc);
if(atd.rc != 999) break;
timeout--;
usleep(10000);
}
rc = atd.rc;
//Condition to check if thread is completed or not yet.
if(atd.thrd_completed_flag == false)
{
//Thread not comepleted within time, so Kill it now.
printf("PJH ------- 10 Seconds Over\n");
thrd_rc = pthread_cancel(th);
printf("PJH ------- Thread Cancelled Immediately \n");
if (thrd_rc != 0)
{
handle_error_en(thrd_rc, "pthread_cancel");
}
printf("\nPJH &&&&&&&& Thread Cancelled Manually\n");
}
thrd_rc = pthread_join(th,NULL);
// some other job .....
}
gdb process_name corefile
显示以下回溯:- 大部分是所有 SQL 库函数。
#0 0xffffe410 in __kernel_vsyscall ()
#1 0x0059fe30 in raise () from /lib/libc.so.6
#2 0x005a1741 in abort () from /lib/libc.so.6
#3 0xdef3f5d7 in ?? () from /usr/lib/libstdc++.so.5
#4 0xdef3f624 in std::terminate() () from /usr/lib/libstdc++.so.5
#5 0xdef3f44c in __gxx_personality_v0 () from /usr/lib/libstdc++.so.5
#6 0x007e1917 in ?? () from /lib/libgcc_s.so.1
#7 0x007e1c70 in _Unwind_ForcedUnwind () from /lib/libgcc_s.so.1
#8 0x007cda46 in _Unwind_ForcedUnwind () from /lib/libpthread.so.0
#9 0x007cb471 in __pthread_unwind () from /lib/libpthread.so.0
#10 0x007c347a in sigcancel_handler () from /lib/libpthread.so.0
#11 <signal handler called>
#12 0xffffe410 in __kernel_vsyscall ()
#13 0x0064decb in semop () from /lib/libc.so.6
#14 0xe0245901 in sqloSSemP () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#15 0xe01e7f3c in sqlccipcrecv(sqlcc_comhandle*, sqlcc_cond*) () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#16 0xe03fe135 in sqlccrecv () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#17 0xe02a0307 in sqljcReceive(sqljCmnMgr*) () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#18 0xe02d0ba3 in sqljrReceive(sqljrDrdaArCb*, db2UCinterface*) () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#19 0xe02c510d in sqljrDrdaArExecute(db2UCinterface*, UCstpInfo*) () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#20 0xe01392bc in CLI_sqlCallProcedure(CLI_STATEMENTINFO*, CLI_ERRORHEADERINFO*) () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#21 0xe00589c7 in SQLExecute2(CLI_STATEMENTINFO*, CLI_ERRORHEADERINFO*) () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#22 0xe0050fc9 in SQLExecute () from /opt/IBM/db2/V9.1/lib32/libdb2.so.1
#23 0x080a81f7 in apcd_in_thread_call (in_apcd_arg=0xbc8e8f34) at dcs_db2_execute.c:357
#24 0x007c4912 in start_thread () from /lib/libpthread.so.0
#25 0x0064c60e in clone () from /lib/libc.so.6