413 lines
17 KiB
C
413 lines
17 KiB
C
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the Netscape Portable Runtime (NSPR).
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998-2000
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#if defined(_PRMWAIT_H)
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#else
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#define _PRMWAIT_H
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#include "prio.h"
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#include "prtypes.h"
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#include "prclist.h"
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PR_BEGIN_EXTERN_C
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/********************************************************************************/
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/********************************************************************************/
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/********************************************************************************/
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/****************************** WARNING ****************************/
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/********************************************************************************/
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/**************************** This is work in progress. *************************/
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/************************** Do not make any assumptions *************************/
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/************************** about the stability of this *************************/
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/************************** API or the underlying imple- ************************/
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/************************** mentation. ************************/
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/********************************************************************************/
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/********************************************************************************/
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/*
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** STRUCTURE: PRWaitGroup
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** DESCRIPTION:
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** The client may define several wait groups in order to semantically
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** tie a collection of file descriptors for a single purpose. This allows
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** easier dispatching of threads that returned with active file descriptors
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** from the wait function.
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*/
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typedef struct PRWaitGroup PRWaitGroup;
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/*
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** ENUMERATION: PRMWStatus
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** DESCRIPTION:
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** This enumeration is used to indicate the completion status of
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** a receive wait object. Generally stated, a positive value indicates
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** that the operation is not yet complete. A zero value indicates
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** success (similar to PR_SUCCESS) and any negative value is an
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** indication of failure. The reason for the failure can be retrieved
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** by calling PR_GetError().
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**
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** PR_MW_PENDING The operation is still pending. None of the other
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** fields of the object are currently valid.
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** PR_MW_SUCCESS The operation is complete and it was successful.
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** PR_MW_FAILURE The operation failed. The reason for the failure
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** can be retrieved by calling PR_GetError().
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** PR_MW_TIMEOUT The amount of time allowed for by the object's
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** 'timeout' field has expired w/o the operation
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** otherwise coming to closure.
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** PR_MW_INTERRUPT The operation was cancelled, either by the client
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** calling PR_CancelWaitFileDesc() or destroying the
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** entire wait group (PR_DestroyWaitGroup()).
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*/
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typedef enum PRMWStatus
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{
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PR_MW_PENDING = 1,
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PR_MW_SUCCESS = 0,
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PR_MW_FAILURE = -1,
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PR_MW_TIMEOUT = -2,
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PR_MW_INTERRUPT = -3
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} PRMWStatus;
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/*
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** STRUCTURE: PRMemoryDescriptor
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** DESCRIPTION:
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** THis is a descriptor for an interval of memory. It contains a
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** pointer to the first byte of that memory and the length (in
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** bytes) of the interval.
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*/
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typedef struct PRMemoryDescriptor
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{
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void *start; /* pointer to first byte of memory */
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PRSize length; /* length (in bytes) of memory interval */
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} PRMemoryDescriptor;
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/*
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** STRUCTURE: PRMWaitClientData
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** DESCRIPTION:
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** An opague stucture for which a client MAY give provide a concrete
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** definition and associate with a receive descriptor. The NSPR runtime
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** does not manage this field. It is completely up to the client.
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*/
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typedef struct PRMWaitClientData PRMWaitClientData;
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/*
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** STRUCTURE: PRRecvWait
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** DESCRIPTION:
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** A receive wait object contains the file descriptor that is subject
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** to the wait and the amount of time (beginning epoch established
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** when the object is presented to the runtime) the the channel should
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** block before abandoning the process.
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**
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** The success of the wait operation will be noted in the object's
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** 'outcome' field. The fields are not valid when the NSPR runtime
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** is in possession of the object.
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**
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** The memory descriptor describes an interval of writable memory
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** in the caller's address space where data from an initial read
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** can be placed. The description may indicate a null interval.
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*/
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typedef struct PRRecvWait
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{
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PRCList internal; /* internal runtime linkages */
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PRFileDesc *fd; /* file descriptor associated w/ object */
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PRMWStatus outcome; /* outcome of the current/last operation */
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PRIntervalTime timeout; /* time allowed for entire operation */
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PRInt32 bytesRecv; /* number of bytes transferred into buffer */
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PRMemoryDescriptor buffer; /* where to store first segment of input data */
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PRMWaitClientData *client; /* pointer to arbitrary client defined data */
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} PRRecvWait;
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/*
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** STRUCTURE: PRMWaitEnumerator
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** DESCRIPTION:
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** An enumeration object is used to store the state of an existing
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** enumeration over a wait group. The opaque object must be allocated
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** by the client and the reference presented on each call to the
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** pseudo-stateless enumerator. The enumeration objects are sharable
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** only in serial fashion.
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*/
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typedef struct PRMWaitEnumerator PRMWaitEnumerator;
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/*
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** FUNCTION: PR_AddWaitFileDesc
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** DESCRIPTION:
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** This function will effectively add a file descriptor to the
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** list of those waiting for network receive. The new descriptor
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** will be semantically tied to the wait group specified.
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**
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** The ownership for the storage pointed to by 'desc' is temporarily
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** passed over the the NSPR runtime. It will be handed back by the
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** function PR_WaitRecvReady().
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**
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** INPUTS
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** group A reference to a PRWaitGroup or NULL. Wait groups are
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** created by calling PR_CreateWaitGroup() and are used
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** to semantically group various file descriptors by the
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** client's application.
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** desc A reference to a valid PRRecvWait. The object of the
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** reference must be preserved and not be modified
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** until its ownership is returned to the client.
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** RETURN
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** PRStatus An indication of success. If equal to PR_FAILUE details
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** of the failure are avaiable via PR_GetError().
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**
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** ERRORS
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** PR_INVALID_ARGUMENT_ERROR
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** Invalid 'group' identifier or duplicate 'desc' object.
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** PR_OUT_OF_MEMORY_ERROR
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** Insuffient memory for internal data structures.
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** PR_INVALID_STATE_ERROR
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** The group is being destroyed.
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*/
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NSPR_API(PRStatus) PR_AddWaitFileDesc(PRWaitGroup *group, PRRecvWait *desc);
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/*
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** FUNCTION: PR_WaitRecvReady
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** DESCRIPTION:
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** PR_WaitRecvReady will block the calling thread until one of the
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** file descriptors that have been added via PR_AddWaitFileDesc is
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** available for input I/O.
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** INPUT
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** group A pointer to a valid PRWaitGroup or NULL (the null
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** group. The function will block the caller until a
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** channel from the wait group becomes ready for receive
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** or there is some sort of error.
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** RETURN
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** PRReciveWait
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** When the caller is resumed it is either returned a
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** valid pointer to a previously added receive wait or
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** a NULL. If the latter, the function has terminated
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** for a reason that can be determined by calling
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** PR_GetError().
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** If a valid pointer is returned, the reference is to the
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** file descriptor contained in the receive wait object.
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** The outcome of the wait operation may still fail, and
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** if it has, that fact will be noted in the object's
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** outcome field. Details can be retrieved from PR_GetError().
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**
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** ERRORS
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** PR_INVALID_ARGUMENT_ERROR
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** The 'group' is not known by the runtime.
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** PR_PENDING_INTERRUPT_ERROR
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The thread was interrupted.
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** PR_INVALID_STATE_ERROR
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** The group is being destroyed.
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*/
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NSPR_API(PRRecvWait*) PR_WaitRecvReady(PRWaitGroup *group);
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/*
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** FUNCTION: PR_CancelWaitFileDesc
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** DESCRIPTION:
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** PR_CancelWaitFileDesc is provided as a means for cancelling operations
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** on objects previously submitted by use of PR_AddWaitFileDesc(). If
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** the runtime knows of the object, it will be marked as having failed
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** because it was interrupted (similar to PR_Interrupt()). The first
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** available thread waiting on the group will be made to return the
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** PRRecvWait object with the outcome noted.
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**
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** INPUTS
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** group The wait group under which the wait receive object was
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** added.
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** desc A pointer to the wait receive object that is to be
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** cancelled.
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** RETURN
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** PRStatus If the wait receive object was located and associated
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** with the specified wait group, the status returned will
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** be PR_SUCCESS. There is still a race condition that would
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** permit the offected object to complete normally, but it
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** is assured that it will complete in the near future.
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** If the receive object or wait group are invalid, the
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** function will return with a status of PR_FAILURE.
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**
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** ERRORS
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** PR_INVALID_ARGUMENT_ERROR
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** The 'group' argument is not recognized as a valid group.
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** PR_COLLECTION_EMPTY_ERROR
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** There are no more receive wait objects in the group's
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** collection.
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** PR_INVALID_STATE_ERROR
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** The group is being destroyed.
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*/
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NSPR_API(PRStatus) PR_CancelWaitFileDesc(PRWaitGroup *group, PRRecvWait *desc);
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/*
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** FUNCTION: PR_CancelWaitGroup
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** DESCRIPTION:
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** PR_CancelWaitGroup is provided as a means for cancelling operations
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** on objects previously submitted by use of PR_AddWaitFileDesc(). Each
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** successive call will return a pointer to a PRRecvWait object that
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** was previously registered via PR_AddWaitFileDesc(). If no wait
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** objects are associated with the wait group, a NULL will be returned.
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** This function should be called in a loop until a NULL is returned
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** to reclaim all the wait objects prior to calling PR_DestroyWaitGroup().
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**
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** INPUTS
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** group The wait group under which the wait receive object was
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** added.
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** RETURN
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** PRRecvWait* If the wait group is valid and at least one receive wait
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** object is present in the group, that object will be
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** marked as PR_MW_INTERRUPT'd and removed from the group's
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** queues. Otherwise a NULL will be returned and the reason
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** for the NULL may be retrieved by calling PR_GetError().
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**
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** ERRORS
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** PR_INVALID_ARGUMENT_ERROR
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** PR_GROUP_EMPTY_ERROR
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*/
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NSPR_API(PRRecvWait*) PR_CancelWaitGroup(PRWaitGroup *group);
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/*
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** FUNCTION: PR_CreateWaitGroup
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** DESCRIPTION:
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** A wait group is an opaque object that a client may create in order
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** to semantically group various wait requests. Each wait group is
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** unique, including the default wait group (NULL). A wait request
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** that was added under a wait group will only be serviced by a caller
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** that specified the same wait group.
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**
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** INPUT
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** size The size of the hash table to be used to contain the
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** receive wait objects. This is just the initial size.
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** It will grow as it needs to, but to avoid that hassle
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** one can suggest a suitable size initially. It should
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** be ~30% larger than the maximum number of receive wait
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** objects expected.
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** RETURN
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** PRWaitGroup If successful, the function will return a pointer to an
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** object that was allocated by and owned by the runtime.
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** The reference remains valid until it is explicitly destroyed
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** by calling PR_DestroyWaitGroup().
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**
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** ERRORS
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** PR_OUT_OF_MEMORY_ERROR
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*/
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NSPR_API(PRWaitGroup*) PR_CreateWaitGroup(PRInt32 size);
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/*
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** FUNCTION: PR_DestroyWaitGroup
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** DESCRIPTION:
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** Undo the effects of PR_CreateWaitGroup(). Any receive wait operations
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** on the group will be treated as if the each had been the target of a
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** PR_CancelWaitFileDesc().
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**
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** INPUT
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** group Reference to a wait group previously allocated using
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** PR_CreateWaitGroup().
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** RETURN
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** PRStatus Will be PR_SUCCESS if the wait group was valid and there
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** are no receive wait objects in that group. Otherwise
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** will indicate PR_FAILURE.
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**
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** ERRORS
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** PR_INVALID_ARGUMENT_ERROR
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** The 'group' argument does not reference a known object.
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** PR_INVALID_STATE_ERROR
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** The group still contains receive wait objects.
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*/
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NSPR_API(PRStatus) PR_DestroyWaitGroup(PRWaitGroup *group);
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/*
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** FUNCTION: PR_CreateMWaitEnumerator
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** DESCRIPTION:
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** The PR_CreateMWaitEnumerator() function returns a reference to an
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** opaque PRMWaitEnumerator object. The enumerator object is required
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** as an argument for each successive call in the stateless enumeration
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** of the indicated wait group.
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**
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** group The wait group that the enumeration is intended to
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** process. It may be be the default wait group (NULL).
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** RETURN
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** PRMWaitEnumerator* group
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** A reference to an object that will be used to store
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** intermediate state of enumerations.
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** ERRORS
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** Errors are indicated by the function returning a NULL.
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** PR_INVALID_ARGUMENT_ERROR
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** The 'group' argument does not reference a known object.
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** PR_OUT_OF_MEMORY_ERROR
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*/
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NSPR_API(PRMWaitEnumerator*) PR_CreateMWaitEnumerator(PRWaitGroup *group);
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/*
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** FUNCTION: PR_DestroyMWaitEnumerator
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** DESCRIPTION:
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** Destroys the object created by PR_CreateMWaitEnumerator(). The reference
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** used as an argument becomes invalid.
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**
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** INPUT
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** PRMWaitEnumerator* enumerator
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** The PRMWaitEnumerator object to destroy.
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** RETURN
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** PRStatus
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** PR_SUCCESS if successful, PR_FAILURE otherwise.
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** ERRORS
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** PR_INVALID_ARGUMENT_ERROR
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** The enumerator is invalid.
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*/
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NSPR_API(PRStatus) PR_DestroyMWaitEnumerator(PRMWaitEnumerator* enumerator);
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/*
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** FUNCTION: PR_EnumerateWaitGroup
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** DESCRIPTION:
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** PR_EnumerateWaitGroup is a thread safe enumerator over a wait group.
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** Each call to the enumerator must present a valid PRMWaitEnumerator
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** rererence and a pointer to the "previous" element returned from the
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** enumeration process or a NULL.
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**
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** An enumeration is started by passing a NULL as the "previous" value.
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** Subsequent calls to the enumerator must pass in the result of the
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** previous call. The enumeration end is signaled by the runtime returning
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** a NULL as the result.
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**
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** Modifications to the content of the wait group are allowed during
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** an enumeration. The effect is that the enumeration may have to be
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** "reset" and that may result in duplicates being returned from the
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** enumeration.
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**
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** An enumeration may be abandoned at any time. The runtime is not
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** keeping any state, so there are no issues in that regard.
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*/
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NSPR_API(PRRecvWait*) PR_EnumerateWaitGroup(
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PRMWaitEnumerator *enumerator, const PRRecvWait *previous);
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PR_END_EXTERN_C
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#endif /* defined(_PRMWAIT_H) */
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/* prmwait.h */
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