c - fork 和现有线程？

Question

在 linux 系统上，子进程是否以与父进程相同的方式查看现有线程？

int main() {

  //create thread 1

  int child_pid = fork();

  if ( 0 == child_pid)
  {
       ..
  }
  else
  {
       ..
  }

由于为子进程复制了整个地址空间，线程的状态会发生什么变化。如果上述段中的线程 1 正在等待条件信号怎么办。在子进程中是否也处于等待状态？

Answer 1

如今 Linux 上的线程试图保持 POSIX 兼容。仅复制调用线程，而不复制其他线程(请注意，例如在 Solaris 上，您可以根据链接到的库选择 fork 的功能)

来自 http://www.opengroup.org/onlinepubs/000095399/functions/fork.html (POSIX 2004):

A process shall be created with a single thread. If a multi-threaded process calls fork(), the new process shall contain a replica of the calling thread and its entire address space, possibly including the states of mutexes and other resources. Consequently, to avoid errors, the child process may only execute async-signal-safe operations until such time as one of the exec functions is called. Fork handlers may be established by means of the pthread_atfork() function in order to maintain application invariants across fork() calls.

fork() 的 POSIX 2018 规范是相似的。