Messages in this thread | | | From | "Hu, Boris" <> | Subject | what's the relationship between tgid, tid and pid ? | Date | Fri, 6 Dec 2002 03:36:21 +0800 |
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Linux 2.5.49 NTPL 0.10
I learned from the kernel source. sys_getpid() returns tgid and sys_gettid() returns pid. Moreover, /kernel/source/fork.c copy_process() 771 if (clone_flags & CLONE_PARENT_SETTID) 772 if (put_user(p->pid, parent_tidptr)) // parent_tidptr is tid in struct pthread .... It seems tid = pid, while tgid is head pthread pid.
But the following lines let me confused. /kernel/source/fork.c copy_process() 893 p->tgid = p->pid; 894 p->group_leader = p; every pthread_create()->sys_clone()->do_fork()->copy_process() p->tgid will be overwritten every time?
any comments? thanks.
Boris ========================= To know what I don't know To learn what I don't know To contribute what I know =========================
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