I want to get the pthread_attr_t of the main thread. Is there any function to achieve this ?
I have look for such function on some websites, for example, https://pubs.opengroup.org/onlinepubs/7908799/xsh/pthread.h.html. But there seems no.
Can anyone help? thanks!
CodePudding user response：
No, there is no simple way to do this, as you have seen.
Instead, you can check your implementation's documentation, which should specify the default or inherited attributes of a process' initial (main()) thread. (For example, in POSIX, the initial thread is joinable.) You can also use the pthread_get* functions to interrogate the initial thread's attributes at run time, but of course you need to know a priori which attributes to look for, since your implementation may have nonstandard attributes.
CodePudding user response：
You can use the family of functions pthread_attr_getxx but as I have been told in the comments, the function did not modify the struct. So it cannot be used. If I don´t find a solution in a while I will delete the comment
CodePudding user response：
| stuff you can do with pthread_attr | in a thread you can get that info with |
|---|---|
| pthread_attr_setaffinity_np | pthread_getaffinity_np |
| pthread_attr_setinheritsched | Thread already exists, you can get current sched. |
| pthread_attr_setschedparam | pthread_getschedparam |
| pthread_attr_setschedpolicy | pthread_getschedparam |
| pthread_attr_setscope | dunno |
| pthread_attr_setdetachstate | dunno |
| pthread_attr_setsigmask_np | pthread_sigmask |
| pthread_attr_setguardsize | On Linux, parse /proc/*/maps. |
| pthread_attr_setstack pthread_attr_setstackaddr pthread_attr_setstacksize |
On Linux, parse /proc/*/maps like glibc does https://github.com/lattera/glibc/blob/master/nptl/pthread_getattr_np.c#L81 |
Note that in your program you can wrap calls to pthread_attr and pthread_create and store the information yourself.
of the main thread
I would guess the main thread has scope PTHREAD_SCOPE_SYSTEM and surely is not detached.