O nás     Inzerce     KontaktSpolehlivé informace o IT již od roku 2011
Hledat
Nepřehlédněte: 2. kolo: Pozoruhodné IT produkty 2020
Správa dokumentů
Digitální transformace
Informační systémy
Hlavní rubriky: Informační systémy, Mobilní technologie, Datová centra, Sítě, IT bezpečnost, Software, Hardware, Zkušenosti a názory, Speciály

Pozoruhodné IT produkty 2020
E-knihy o IT zdarma
Odborné IT konference BusinessIT
Manuál Linux
[Linux manuál]

aio_cancel: zrušit asynchronní žádost o vstup / výstup (REÁLNÝ ČAS)

Originální popis anglicky: aio_cancel - cancel an asynchronous I/O request ( REALTIME)

Návod, kniha: POSIX Programmer's Manual

STRUČNĚ

#include <aio.h>
 
 
int aio_cancel(int fildes, struct aiocb *aiocbp );
 

POPIS / INSTRUKCE

The aio_cancel() function shall attempt to cancel one or more asynchronous I/O requests currently outstanding against file descriptor fildes. The aiocbp argument points to the asynchronous I/O control block for a particular request to be canceled. If aiocbp is NULL, then all outstanding cancelable asynchronous I/O requests against fildes shall be canceled.
Normal asynchronous notification shall occur for asynchronous I/O operations that are successfully canceled. If there are requests that cannot be canceled, then the normal asynchronous completion process shall take place for those requests when they are completed.
For requested operations that are successfully canceled, the associated error status shall be set to [ECANCELED] and the return status shall be -1. For requested operations that are not successfully canceled, the aiocbp shall not be modified by aio_cancel().
If aiocbp is not NULL, then if fildes does not have the same value as the file descriptor with which the asynchronous operation was initiated, unspecified results occur.
Which operations are cancelable is implementation-defined.

NÁVRATOVÁ HODNOTA

The aio_cancel() function shall return the value AIO_CANCELED to the calling process if the requested operation(s) were canceled. The value AIO_NOTCANCELED shall be returned if at least one of the requested operation(s) cannot be canceled because it is in progress. In this case, the state of the other operations, if any, referenced in the call to aio_cancel() is not indicated by the return value of aio_cancel(). The application may determine the state of affairs for these operations by using aio_error(). The value AIO_ALLDONE is returned if all of the operations have already completed. Otherwise, the function shall return -1 and set errno to indicate the error.

CHYBY / ERRORY

The aio_cancel() function shall fail if:
EBADF
The fildes argument is not a valid file descriptor.
 
The following sections are informative.

PŘÍKLADY POUŽITÍ

None.

APPLICATION USAGE

The aio_cancel() function is part of the Asynchronous Input and Output option and need not be available on all implementations.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SOUVISEJÍCÍ

aio_read() , aio_write() , the Base Definitions volume of IEEE Std 1003.1-2001, <aio.h> Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
2003 IEEE/The Open Group
©2011-2020 BusinessIT.cz, ISSN 1805-0522 | Názvy použité v textech mohou být ochrannými známkami příslušných vlastníků.
Provozovatel: Bispiral, s.r.o., kontakt: BusinessIT(at)Bispiral.com | Inzerce: Best Online Media, s.r.o., zuzana@online-media.cz
O vydavateli | Pravidla webu BusinessIT.cz a ochrana soukromí | pg(8785)