xrootd
XrdPosixCallBack.hh
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1 #ifndef __POSIX_CALLBACK_HH__
2 #define __POSIX_CALLBACK_HH__
3 /******************************************************************************/
4 /* */
5 /* X r d P o s i x C a l l B a c k . h h */
6 /* */
7 /* (c) 2010 by the Board of Trustees of the Leland Stanford, Jr., University */
8 /* All Rights Reserved */
9 /* Produced by Andrew Hanushevsky for Stanford University under contract */
10 /* DE-AC02-76-SFO0515 with the Department of Energy */
11 /* */
12 /* This file is part of the XRootD software suite. */
13 /* */
14 /* XRootD is free software: you can redistribute it and/or modify it under */
15 /* the terms of the GNU Lesser General Public License as published by the */
16 /* Free Software Foundation, either version 3 of the License, or (at your */
17 /* option) any later version. */
18 /* */
19 /* XRootD is distributed in the hope that it will be useful, but WITHOUT */
20 /* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */
21 /* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */
22 /* License for more details. */
23 /* */
24 /* You should have received a copy of the GNU Lesser General Public License */
25 /* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */
26 /* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */
27 /* */
28 /* The copyright holder's institutional names and contributor's names may not */
29 /* be used to endorse or promote products derived from this software without */
30 /* specific prior written permission of the institution or contributor. */
31 /******************************************************************************/
32 
33 // This abstract class defines the callback interface for file open() calls.
34 // It is passed when using the XrdPosixXrootd::Open() call. When passed, the
35 // open request will be done in the background. When a callback object is
36 // supplied, Open() will *always* return -1. However, if started successfully,
37 // Open() will return -1 with errno set to EINPROGRESS. Otherwise, errno will
38 // contain the reason the Open() request immediately failed. Upon completion,
39 // the callback's Compete() method is invoked. The Result parameter will either
40 // be a non-negative file descriptor or -errno indicating that the Open()
41 // failed. Note that the caller is responsible for deleting the callback object
42 // after it has been invoked. Note that callbacks will be executed in a
43 // separate thread unless open() is called with O_SYNC or maxThreads is zero.
44 // WARNING: If O_SYNC or maxThreads is zero, then the callback must *not*
45 // issue any filesystem calls using the supplied file descriptor.
46 // Ignoring this will produce undetermined results including possible
47 // deadlock. Synchrnous callbacks are only meant to support private
48 // thread management.
49 
51 {
52 public:
53 
54 virtual void Complete(int Result) = 0;
55 
57 virtual ~XrdPosixCallBack() {}
58 };
59 #endif
XrdPosixCallBack()
Definition: XrdPosixCallBack.hh:56
Definition: XrdPosixCallBack.hh:50
virtual void Complete(int Result)=0
virtual ~XrdPosixCallBack()
Definition: XrdPosixCallBack.hh:57