Linux c++进程状态中的+是什么意思

我做了test.cpp个，然后编辑了这个.

int main() {
    while(1);
}

g++ test.cpp个

和ps -aux | grep a.out.

进程状态a.out为R+.

是.当然，这个过程是无限运行的.

但是，我不明白这+

在ps手册中，+在前台进程组中.

我不知道a.out在前台进程组是什么意思.

PROCESS STATE CODES         
       Here are the different values that the s, stat and state output
       specifiers (header "STAT" or "S") will display to describe the
       state of a process:

               D    uninterruptible sleep (usually IO)
               I    Idle kernel thread
               R    running or runnable (on run queue)
               S    interruptible sleep (waiting for an event to
                    complete)
               T    stopped by job control signal
               t    stopped by debugger during the tracing
               W    paging (not valid since the 2.6.xx kernel)
               X    dead (should never be seen)
               Z    defunct ("zombie") process, terminated but not
                    reaped by its parent

       For BSD formats and when the stat keyword is used, additional
       characters may be displayed:

               <    high-priority (not nice to other users)
               N    low-priority (nice to other users)
               L    has pages locked into memory (for real-time and
                    custom IO)
               s    is a session leader
               l    is multi-threaded (using CLONE_THREAD, like NPTL
                    pthreads do)
               +    is in the foreground process group