this is the quit code:

send(my_socket,(const char*)data,datasize,0):

the thread quit after this code, some minutes later which means that it send well in first some minutes.

printf("before");
 send(my_socket,(const char*)data,datasize,0):
printf("after");

it will log out the "before" and then the thread quit.
I have add some exception code

try catch(…){printf(“this is exception”);}

but nothing print out.it seems that there is no exception.

the thread is using std::thread.

std::thread thread([&]{
...do some code.
send(...)....
});
thread.detach();