如何检查当前线程是否是 linux 上的主线程？看起来 gettid() 只返回一个 pid，但似乎 linux 不保证 main() 的线程总是有一个常量和统一的 pid。
这样做的原因是我有一个自动并行化正在进行，我想确保 pthread_create() 不会在已经在由 pthread_create() 创建的线程上运行的函数中调用。
最佳答案
对于 Linux:
如果 getpid() 返回与 gettid() 相同的结果，则它是主线程。
int i_am_the_main_thread(void)
{
return getpid() == gettid();
}
来自 man gettid :
gettid() returns the caller's thread ID (TID). In a single-threaded process, the thread ID is equal to the process ID (PID, as returned by getpid(2)). In a multithreaded process, all threads have the same PID, but each one has a unique TID.
来自 man clone :
Thread groups were a feature added in Linux 2.4 to support the POSIX threads notion of a set of threads that share a single PID. Internally, this shared PID is the so-called thread group identifier (TGID) for the thread group. Since Linux 2.4, calls to getpid(2) return the TGID of the caller.
The threads within a group can be distinguished by their (system-wide) unique thread IDs (TID). A new thread's TID is available as the function result returned to the caller of clone(), and a thread can obtain its own TID using gettid(2).
关于c++ - 检查当前线程是否为主线程，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20530218/