#include <iostream>
#include <unordered_map>
#include <vector>
#include <thread>
using namespace std;
// not POD
struct A {
std::unordered_map<int, int> m_test;
};
struct B{
thread_local static A a;
};
thread_local A B::a = A();
B b;
void func(){
b.a.m_test[0] ;
}
int main() {
vector<thread> Threads;
for (int i = 0; i < 10; i ) {
Threads.push_back(thread(func));
}
for (int i = 0; i < 10; i ) {
Threads[i].join();
}
return 0;
}
the code snippet is showed as above.
I built the same code in Linux: gcc 4.8.5 and MacOS:clang13.1.6 , outcome is the different . In Linux, An error occurred as 17703 Floating point exception(core dumped)
, but in MacOS there was no error occurred.
I know thread_local can use in POD type after c 11, but here I use the unordered_map in struct, which internal memory is in the heap, not in the static or global storage area. So I wonder if this is because of how different compilers implement the C standard? And how can I solve this runtime error on the linux platform?
CodePudding user response:
Based on testing on compiler explorer, this seems to be a GCC bug fixed in 2019 for versions 9 , 8.4 and 7.5 . The code should work fine as posted. There is nothing wrong with it.
Probably it is this bug.
I recommend you install and use a more up-to-date version of GCC.