Valgrind 在空白程序上显示大量 memory 泄漏

Question

我正在尝试学习如何使用 valgrind，因此我编写了以下程序：

// no imports in the program either
int main(void) {
    return 0;
}

据我所知，这应该会泄漏任何 memory ，所以我应该得到 valgrind 的回应，表明这一点。 但是，这是 valgrind 显示的内容：

$ gcc strings.c -o strings.out && valgrind ./strings.out

==49859== HEAP SUMMARY:
==49859==     in use at exit: 19,158 bytes in 165 blocks
==49859==   total heap usage: 186 allocs, 21 frees, 27,606 bytes allocated
==49859== 
==49859== LEAK SUMMARY:
==49859==    definitely lost: 0 bytes in 0 blocks
==49859==    indirectly lost: 0 bytes in 0 blocks
==49859==      possibly lost: 8,840 bytes in 7 blocks
==49859==    still reachable: 10,318 bytes in 158 blocks
==49859==         suppressed: 0 bytes in 0 blocks

关于这个的几个问题：

• 为什么最后说使用了 19,158 个字节？ 我的想法是最后应该有零字节，因为我什至没有定义任何东西。
• 左边的49859是什么意思？
• 最后，分配的186 allocs, 21 frees, 27,606 bytes allocated从何而来？

更新：

这似乎是一个以 Mac 为中心的错误，并且在 Google 中似乎在较新版本的 OSX 上很常见。 在 ubuntu 上运行相同的东西似乎很好：

==5689== Command: ./main.out
==5689== 
Hello
==5689== 
==5689== HEAP SUMMARY:
==5689==     in use at exit: 0 bytes in 0 blocks
==5689==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==5689== 
==5689== All heap blocks were freed -- no leaks are possible
==5689== 
==5689== For counts of detected and suppressed errors, rerun with: -v
==5689== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)