Linux Manual Pages

Free Software * Books

Source Code

Free Media

Linux

IO_CANCEL

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
VERSIONS
CONFORMING TO
NOTES
SEE ALSO
COLOPHON

NAME

io_cancel − cancel an outstanding asynchronous I/O operation

SYNOPSIS

#include <linux/aio_abi.h> /* Defines needed types */

int io_cancel(aio_context_t ctx_id, struct iocb *iocb,
struct io_event *result);

Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION

The io_cancel() system call attempts to cancel an asynchronous I/O operation previously submitted with io_submit(2). The iocb argument describes the operation to be canceled and the ctx_id argument is the AIO context to which the operation was submitted. If the operation is successfully canceled, the event will be copied into the memory pointed to by result without being placed into the completion queue.

RETURN VALUE

On success, io_cancel() returns 0. For the failure return, see NOTES.

ERRORS

	EAGAIN		The iocb specified was not canceled.
	EFAULT		One of the data structures points to invalid data.
	EINVAL		The AIO context specified by ctx_id is invalid.
	ENOSYS		io_cancel() is not implemented on this architecture.

VERSIONS

The asynchronous I/O system calls first appeared in Linux 2.5.

CONFORMING TO

io_cancel() is Linux-specific and should not be used in programs that are intended to be portable.

NOTES

Glibc does not provide a wrapper function for this system call. You could invoke it using syscall(2). But instead, you probably want to use the io_cancel() wrapper function provided by libaio.

Note that the libaio wrapper function uses a different type (io_context_t) for the ctx_id argument. Note also that the libaio wrapper does not follow the usual C library conventions for indicating errors: on error it returns a negated error number (the negative of one of the values listed in ERRORS). If the system call is invoked via syscall(2), then the return value follows the usual conventions for indicating an error: −1, with errno set to a (positive) value that indicates the error.

COLOPHON

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/.

Opportunity

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

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.

Free Books

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.

Education

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.