get_robust_list

       #include <linux/futex.h>
       #include <sys/types.h>
       #include <syscall.h>

       long get_robust_list(int pid, struct robust_list_head **head_ptr,
                            size_t *len_ptr);
       long set_robust_list(struct robust_list_head *head, size_t len);

       Note: There are no glibc wrappers for these system calls; see NOTES.

DESCRIPTION
       The  robust  futex implementation needs to maintain per-thread lists of
       the robust futexes which are to be  unlocked  when  the  thread  exits.
       These  lists  are  managed  in user space; the kernel is notified about
       only the location of the head of the list.

       The get_robust_list() system call returns the head of the robust  futex
       list  of  the thread whose thread ID is specified in pid.  If pid is 0,
       the head of the list for the calling thread is returned.  The list head
       is  stored  in  the  location  pointed to by head_ptr.  The size of the
       object pointed to by **head_ptr is stored in len_ptr.

       The set_robust_list() system call requests the  kernel  to  record  the
       head  of  the  list of robust futexes owned by the calling thread.  The
       head argument is the list head to record.  The len argument  should  be
       sizeof(*head).

RETURN VALUE
       The  set_robust_list()  and  get_robust_list() system calls return zero
       when the operation is successful, an error code otherwise.

ERRORS
       The set_robust_list() system call can fail with the following error:

       EINVAL len does not equal sizeof(struct robust_list_head).

       The get_robust_list() system call can fail with the following errors:

       EPERM  The calling process does not have permission to see  the  robust
              futex  list  of  the thread with the thread ID pid, and does not
              have the CAP_SYS_PTRACE capability.

       ESRCH  No thread with the thread ID pid could be found.

       EFAULT The head of the robust futex list can't be stored at  the  loca-
              tion head.

VERSIONS
       These system calls were added in Linux 2.6.17.

NOTES
       These  system  calls are not needed by normal applications.  No support
       for them is provided in glibc.  In the unlikely event that you want  to
       call them directly, use syscall(2).
       This page is part of release 4.04 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       http://www.kernel.org/doc/man-pages/.

Linux                             2015-12-28                GET_ROBUST_LIST(2)
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