get_robust_list, set_robust_list − get/set list of robust futexes
#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.
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 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).
The set_robust_list() and get_robust_list() system calls return zero when the operation is successful, an error code otherwise.
The set_robust_list() system call can fail with the following error:
EINVAL |
len does not match the size of structure struct robust_list_head expected by kernel. |
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 location head. |
These system calls were added in Linux 2.6.17. No library support is provided; use syscall(2).
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).
A thread can have only one robust futex list; therefore applications that wish to use this functionality should use the robust mutexes provided by glibc.
Documentation/robust-futexes.txt and Documentation/robust-futex-ABI.txt in the Linux kernel source tree
This page is part of release 3.69 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/.
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.