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GET_ROBUST_LIST(2)            Linux System Calls            GET_ROBUST_LIST(2)



NAME
       get_robust_list, set_robust_list - get/set the list of robust futexes

SYNOPSIS
       #include <linux/futex.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);

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

       get_robust_list  returns  the head of the robust futex list of the thread with TID defined by the pid argument.
       If pid is 0, the returned head belongs to the current thread.  head_ptr is the pointer to the head of the  list
       of  robust  futexes.  The get_robust_list function stores the address of the head of the list here.  len_ptr is
       the pointer to the length variable.  get_robust_list stores sizeof(**head_ptr) here.

       set_robust_list sets the head of the list of robust futexes owned by the current thread to head.   len  is  the
       size of *head.


RETURN VALUE
       The  set_robust_list  and get_robust_list functions return zero when the operation is successful, an error code
       otherwise.


ERRORS
       The set_robust_list function fails with EINVAL if the len value does not match the  size  of  structure  struct
       robust_list_head expected by kernel.

       The get_robust_list function fails with EPERM if the current process does not have permission to see the robust
       futex list of the thread with the TID pid, ESRCH if a thread with the TID pid does not exist, or EFAULT if  the
       head of the robust futex list can't be stored in the space specified by the head argument.


APPLICATION USAGE
       A thread can have only one robust futex list; therefore applications that wish to use this functionality should
       use robust mutexes provided by glibc.

       The system call is only available for debugging purposes and is not needed for normal operations.

       Both system calls are not available to application  programs  as  functions;  they  can  be  called  using  the
       syscall(3) function.


SEE ALSO
       futex(2), pthread_mutexattr_setrobust_np(3)



Linux                            8 August 2006              GET_ROBUST_LIST(2)