Current File : //usr/src/vboxhost-6.0.14/vboxdrv/include/iprt/semaphore.h
/** @file
* IPRT - Semaphore.
*/
/*
* Copyright (C) 2006-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
#ifndef IPRT_INCLUDED_semaphore_h
#define IPRT_INCLUDED_semaphore_h
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif
#include <iprt/cdefs.h>
#include <iprt/types.h>
#if defined(RT_LOCK_STRICT_ORDER) && defined(IN_RING3)
# include <iprt/lockvalidator.h>
#endif
RT_C_DECLS_BEGIN
/** @defgroup grp_rt_sems RTSem - Semaphores
*
* This module implements all kinds of event and mutex semaphores; in addition
* to these, IPRT implements "critical sections", which are fast recursive
* mutexes (see @ref grp_rt_critsect ). C++ users may find @ref grp_rt_cpp_lock
* interesting.
*
* @ingroup grp_rt
* @{
*/
/** @name Generic Semaphore Wait Flags.
*
* @remarks Exactly one of RTSEMWAIT_FLAGS_RELATIVE and
* RTSEMWAIT_FLAGS_ABSOLUTE must be set, unless
* RTSEMWAIT_FLAGS_INDEFINITE is used.
*
* Exactly one of RTSEMWAIT_FLAGS_NANOSECS and
* RTSEMWAIT_FLAGS_MILLISECS must be set, unless
* RTSEMWAIT_FLAGS_INDEFINITE is used.
*
* Exactly one of RTSEMWAIT_FLAGS_RESUME and RTSEMWAIT_FLAGS_NORESUME
* must be set.
*
* The interruptible vs resume stuff is ring-0 vs ring-3 semantics.
*
* @{ */
/** The timeout is relative. */
#define RTSEMWAIT_FLAGS_RELATIVE RT_BIT_32(0)
/** The timeout is absolute. */
#define RTSEMWAIT_FLAGS_ABSOLUTE RT_BIT_32(1)
/** The timeout is specified in nanoseconds. */
#define RTSEMWAIT_FLAGS_NANOSECS RT_BIT_32(2)
/** The timeout is specified in milliseconds. */
#define RTSEMWAIT_FLAGS_MILLISECS RT_BIT_32(3)
/** Indefinite wait.
* The relative/absolute and nano-/millisecond flags are ignored. */
#define RTSEMWAIT_FLAGS_INDEFINITE RT_BIT_32(4)
/** Mask covering the time related bits. */
#define RTSEMWAIT_FLAGS_TIME_MASK UINT32_C(0x0000001f)
/** Interruptible wait. */
#define RTSEMWAIT_FLAGS_INTERRUPTIBLE RT_BIT_32(5)
/** No automatic resume, same as interruptible. */
#define RTSEMWAIT_FLAGS_NORESUME RTSEMWAIT_FLAGS_INTERRUPTIBLE
/** Uninterruptible wait. */
#define RTSEMWAIT_FLAGS_UNINTERRUPTIBLE RT_BIT_32(6)
/** Resume on interrupt, same as uninterruptible. */
#define RTSEMWAIT_FLAGS_RESUME RTSEMWAIT_FLAGS_UNINTERRUPTIBLE
/** Macro for validate the flags. */
#define RTSEMWAIT_FLAGS_ARE_VALID(fFlags) \
( !((fFlags) & UINT32_C(0xffffff80)) \
&& ( ((fFlags) & RTSEMWAIT_FLAGS_INDEFINITE) \
? ( (((fFlags) & UINT32_C(0x20))) ^ (((fFlags) >> 1) & UINT32_C(0x20)) ) == UINT32_C(0x20) \
: ( (((fFlags) & UINT32_C(0x25))) ^ (((fFlags) >> 1) & UINT32_C(0x25)) ) == UINT32_C(0x25) ))
/** @} */
/** @defgroup grp_rt_sems_event RTSemEvent - Single Release Event Semaphores
*
* Event semaphores can be used for inter-thread communication when one thread
* wants to notify another thread that something happened. A thread can block
* ("wait") on an event semaphore until it is signalled by another thread; see
* RTSemEventCreate, RTSemEventSignal and RTSemEventWait.
*
* @{ */
/**
* Create an event semaphore.
*
* @returns iprt status code.
* @param phEventSem Where to store the handle to the newly created
* event semaphore.
*/
RTDECL(int) RTSemEventCreate(PRTSEMEVENT phEventSem);
/**
* Create an event semaphore.
*
* @returns iprt status code.
* @param phEventSem Where to store the handle to the newly created
* event semaphore.
* @param fFlags Flags, any combination of the
* RTSEMEVENT_FLAGS_XXX \#defines.
* @param hClass The class (no reference consumed). Since we
* don't do order checks on event semaphores, the
* use of the class is limited to controlling the
* timeout threshold for deadlock detection.
* @param pszNameFmt Name format string for the lock validator,
* optional (NULL). Max length is 32 bytes.
* @param ... Format string arguments.
*/
RTDECL(int) RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
const char *pszNameFmt, ...) RT_IPRT_FORMAT_ATTR_MAYBE_NULL(4, 5);
/** @name RTSemMutexCreateEx flags
* @{ */
/** Disables lock validation. */
#define RTSEMEVENT_FLAGS_NO_LOCK_VAL UINT32_C(0x00000001)
/** Bootstrap hack for use with certain memory allocator locks only! */
#define RTSEMEVENT_FLAGS_BOOTSTRAP_HACK UINT32_C(0x00000004)
/** @} */
/**
* Destroy an event semaphore.
*
* @returns iprt status code.
* @param hEventSem Handle of the event semaphore. NIL_RTSEMEVENT
* is quietly ignored (VINF_SUCCESS).
*/
RTDECL(int) RTSemEventDestroy(RTSEMEVENT hEventSem);
/**
* Signal an event semaphore.
*
* The event semaphore will be signaled and automatically reset after exactly
* one thread have successfully returned from RTSemEventWait() after
* waiting/polling on that semaphore.
*
* @returns iprt status code.
* @param hEventSem The event semaphore to signal.
*
* @remarks ring-0: This works when preemption is disabled. However it is
* system specific whether it works in interrupt context or with
* interrupts disabled.
*
* ring-0/Darwin: This works when interrupts are disabled and thereby
* in interrupt context, except it cannot race semaphore destruction as
* the allocator does not work under these circumstances.
*/
RTDECL(int) RTSemEventSignal(RTSEMEVENT hEventSem);
/**
* Wait for the event semaphore to be signaled, resume on interruption.
*
* This function will resume if the wait is interrupted by an async system event
* (like a unix signal) or similar.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param hEventSem The event semaphore to wait on.
* @param cMillies Number of milliseconds to wait.
*/
RTDECL(int) RTSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies);
/**
* Wait for the event semaphore to be signaled, return on interruption.
*
* This function will not resume the wait if interrupted.
*
* @returns iprt status code.
* @param hEventSem The event semaphore to wait on.
* @param cMillies Number of milliseconds to wait.
*/
RTDECL(int) RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies);
/**
* Extended API for waiting on an event semaphore to be signaled.
*
* @returns IPRT status code.
* @param hEventSem The event semaphore to wait on.
* @param fFlags Combination of RTSEMWAIT_FLAGS_XXX.
* @param uTimeout The timeout, ignored if
* RTSEMWAIT_FLAGS_INDEFINITE is set in @a flags.
* Whether this is absolute or relative,
* milliseconds or nanoseconds depends on the @a
* fFlags value. Do not pass RT_INDEFINITE_WAIT
* here, use RTSEMWAIT_FLAGS_INDEFINITE instead.
*/
RTDECL(int) RTSemEventWaitEx(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout);
/**
* Debug version of RTSemEventWaitEx that tracks the location.
*
* @returns IPRT status code, see RTSemEventWaitEx.
* @param hEventSem The event semaphore to wait on.
* @param fFlags See RTSemEventWaitEx.
* @param uTimeout See RTSemEventWaitEx.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemEventWaitExDebug(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout,
RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Gets the best timeout resolution that RTSemEventWaitEx can do.
*
* @returns The resolution in nanoseconds.
*/
RTDECL(uint32_t) RTSemEventGetResolution(void);
/**
* Sets the signaller thread to one specific thread.
*
* This is only used for validating usage and deadlock detection. When used
* after calls to RTSemEventAddSignaller, the specified thread will be the only
* signalling thread.
*
* @param hEventSem The event semaphore.
* @param hThread The thread that will signal it. Pass
* NIL_RTTHREAD to indicate that there is no
* special signalling thread.
*/
RTDECL(void) RTSemEventSetSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread);
/**
* To add more signalling threads.
*
* First call RTSemEventSetSignaller then add further threads with this.
*
* @param hEventSem The event semaphore.
* @param hThread The thread that will signal it. NIL_RTTHREAD is
* not accepted.
*/
RTDECL(void) RTSemEventAddSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread);
/**
* To remove a signalling thread.
*
* Reverts work done by RTSemEventAddSignaller and RTSemEventSetSignaller.
*
* @param hEventSem The event semaphore.
* @param hThread A previously added thread.
*/
RTDECL(void) RTSemEventRemoveSignaller(RTSEMEVENT hEventSem, RTTHREAD hThread);
/** @} */
/** @defgroup grp_rt_sems_event_multi RTSemEventMulti - Multiple Release Event Semaphores
*
* A variant of @ref grp_rt_sems_event where all threads will be unblocked when
* signalling the semaphore.
*
* @{ */
/**
* Creates a multiple release event semaphore.
*
* @returns iprt status code.
* @param phEventMultiSem Where to store the handle to the newly created
* multiple release event semaphore.
*/
RTDECL(int) RTSemEventMultiCreate(PRTSEMEVENTMULTI phEventMultiSem);
/**
* Creates a multiple release event semaphore.
*
* @returns iprt status code.
* @param phEventMultiSem Where to store the handle to the newly created
* multiple release event semaphore.
* @param fFlags Flags, any combination of the
* RTSEMEVENTMULTI_FLAGS_XXX \#defines.
* @param hClass The class (no reference consumed). Since we
* don't do order checks on event semaphores, the
* use of the class is limited to controlling the
* timeout threshold for deadlock detection.
* @param pszNameFmt Name format string for the lock validator,
* optional (NULL). Max length is 32 bytes.
* @param ... Format string arguments.
*/
RTDECL(int) RTSemEventMultiCreateEx(PRTSEMEVENTMULTI phEventMultiSem, uint32_t fFlags, RTLOCKVALCLASS hClass,
const char *pszNameFmt, ...) RT_IPRT_FORMAT_ATTR_MAYBE_NULL(4, 5);
/** @name RTSemMutexCreateEx flags
* @{ */
/** Disables lock validation. */
#define RTSEMEVENTMULTI_FLAGS_NO_LOCK_VAL UINT32_C(0x00000001)
/** @} */
/**
* Destroy an event multi semaphore.
*
* @returns iprt status code.
* @param hEventMultiSem The multiple release event semaphore. NIL is
* quietly ignored (VINF_SUCCESS).
*/
RTDECL(int) RTSemEventMultiDestroy(RTSEMEVENTMULTI hEventMultiSem);
/**
* Signal an event multi semaphore.
*
* @returns iprt status code.
* @param hEventMultiSem The multiple release event semaphore.
*
* @remarks ring-0: This works when preemption is disabled. However it is
* system specific whether it works in interrupt context or with
* interrupts disabled.
*
* ring-0/Darwin: This works when interrupts are disabled and thereby
* in interrupt context, except it cannot race semaphore destruction as
* the allocator does not work under these circumstances.
*/
RTDECL(int) RTSemEventMultiSignal(RTSEMEVENTMULTI hEventMultiSem);
/**
* Resets an event multi semaphore to non-signaled state.
*
* @returns iprt status code.
* @param hEventMultiSem The multiple release event semaphore.
*/
RTDECL(int) RTSemEventMultiReset(RTSEMEVENTMULTI hEventMultiSem);
/**
* Wait for the event multi semaphore to be signaled, resume on interruption.
*
* This function will resume if the wait is interrupted by an async
* system event (like a unix signal) or similar.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param hEventMultiSem The multiple release event semaphore.
* @param cMillies Number of milliseconds to wait.
*/
RTDECL(int) RTSemEventMultiWait(RTSEMEVENTMULTI hEventMultiSem, RTMSINTERVAL cMillies);
/**
* Wait for the event multi semaphore to be signaled, return on interruption.
*
* This function will not resume the wait if interrupted.
*
* @returns iprt status code.
* @param hEventMultiSem The multiple release event semaphore.
* @param cMillies Number of milliseconds to wait.
* @todo Rename to RTSemEventMultiWaitIntr since it is mainly for
* ring-0 consumption.
*/
RTDECL(int) RTSemEventMultiWaitNoResume(RTSEMEVENTMULTI hEventMultiSem, RTMSINTERVAL cMillies);
/**
* Extended API for waiting on an event semaphore to be signaled.
*
* @returns IPRT status code.
* @param hEventMultiSem The multiple release event semaphore to wait
* on.
* @param fFlags Combination of the RTSEMWAIT_FLAGS_XXX.
* @param uTimeout The timeout, ignored if
* RTSEMWAIT_FLAGS_INDEFINITE is set in @a flags.
* Whether this is absolute or relative,
* milliseconds or nanoseconds depends on the @a
* fFlags value. Do not pass RT_INDEFINITE_WAIT
* here, use RTSEMWAIT_FLAGS_INDEFINITE instead.
*/
RTDECL(int) RTSemEventMultiWaitEx(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout);
/**
* Debug version of RTSemEventMultiWaitEx that tracks the location.
* @returns IPRT status code, see RTSemEventMultiWaitEx.
* @param hEventMultiSem The multiple release event semaphore handle.
* @param fFlags See RTSemEventMultiWaitEx.
* @param uTimeout See RTSemEventMultiWaitEx.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemEventMultiWaitExDebug(RTSEMEVENTMULTI hEventMultiSem, uint32_t fFlags, uint64_t uTimeout,
RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Gets the best timeout resolution that RTSemEventMultiWaitEx can do.
*
* @returns The resolution in nanoseconds.
*/
RTDECL(uint32_t) RTSemEventMultiGetResolution(void);
/**
* Sets the signaller thread to one specific thread.
*
* This is only used for validating usage and deadlock detection. When used
* after calls to RTSemEventAddSignaller, the specified thread will be the only
* signalling thread.
*
* @param hEventMultiSem The multiple release event semaphore.
* @param hThread The thread that will signal it. Pass
* NIL_RTTHREAD to indicate that there is no
* special signalling thread.
*/
RTDECL(void) RTSemEventMultiSetSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread);
/**
* To add more signalling threads.
*
* First call RTSemEventSetSignaller then add further threads with this.
*
* @param hEventMultiSem The multiple release event semaphore.
* @param hThread The thread that will signal it. NIL_RTTHREAD is
* not accepted.
*/
RTDECL(void) RTSemEventMultiAddSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread);
/**
* To remove a signalling thread.
*
* Reverts work done by RTSemEventAddSignaller and RTSemEventSetSignaller.
*
* @param hEventMultiSem The multiple release event semaphore.
* @param hThread A previously added thread.
*/
RTDECL(void) RTSemEventMultiRemoveSignaller(RTSEMEVENTMULTI hEventMultiSem, RTTHREAD hThread);
/** @} */
/** @defgroup grp_rt_sems_mutex RTSemMutex - Mutex semaphores.
*
* Mutex semaphores protect a section of code or data to which access must be
* exclusive. Only one thread can hold access to a critical section at one
* time. See RTSemMutexCreate, RTSemMutexRequest and RTSemMutexRelease.
*
* @remarks These are less efficient than "fast mutexes" and "critical
* sections", which IPRT implements as well; see @ref
* grp_rt_sems_fast_mutex and @ref grp_rt_critsect .
*
* @{ */
/**
* Create a mutex semaphore.
*
* @returns iprt status code.
* @param phMutexSem Where to store the mutex semaphore handle.
*/
RTDECL(int) RTSemMutexCreate(PRTSEMMUTEX phMutexSem);
/**
* Creates a read/write semaphore.
*
* @returns iprt status code.
* @param phMutexSem Where to store the handle to the newly created
* mutex semaphore.
* @param fFlags Flags, any combination of the
* RTSEMMUTEX_FLAGS_XXX \#defines.
* @param hClass The class (no reference consumed). If NIL, no
* lock order validation will be performed on this
* lock.
* @param uSubClass The sub-class. This is used to define lock
* order within a class. RTLOCKVAL_SUB_CLASS_NONE
* is the recommended value here.
* @param pszNameFmt Name format string for the lock validator,
* optional (NULL). Max length is 32 bytes.
* @param ... Format string arguments.
*/
RTDECL(int) RTSemMutexCreateEx(PRTSEMMUTEX phMutexSem, uint32_t fFlags, RTLOCKVALCLASS hClass, uint32_t uSubClass,
const char *pszNameFmt, ...) RT_IPRT_FORMAT_ATTR_MAYBE_NULL(5, 6);
/** @name RTSemMutexCreateEx flags
* @{ */
/** Disables lock validation. */
#define RTSEMMUTEX_FLAGS_NO_LOCK_VAL UINT32_C(0x00000001)
/** @} */
/**
* Destroy a mutex semaphore.
*
* @returns iprt status code.
* @param hMutexSem The mutex semaphore to destroy. NIL is quietly
* ignored (VINF_SUCCESS).
*/
RTDECL(int) RTSemMutexDestroy(RTSEMMUTEX hMutexSem);
/**
* Changes the lock validator sub-class of the mutex semaphore.
*
* It is recommended to try make sure that nobody is using this semaphore while
* changing the value.
*
* @returns The old sub-class. RTLOCKVAL_SUB_CLASS_INVALID is returns if the
* lock validator isn't compiled in or either of the parameters are
* invalid.
* @param hMutexSem The handle to the mutex semaphore.
* @param uSubClass The new sub-class value.
*/
RTDECL(uint32_t) RTSemMutexSetSubClass(RTSEMMUTEX hMutexSem, uint32_t uSubClass);
/**
* Request ownership of a mutex semaphore, resume on interruption.
*
* This function will resume if the wait is interrupted by an async
* system event (like a unix signal) or similar.
*
* The same thread may request a mutex semaphore multiple times,
* a nested counter is kept to make sure it's released on the right
* RTSemMutexRelease() call.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param hMutexSem The mutex semaphore to request ownership over.
* @param cMillies The number of milliseconds to wait.
*/
RTDECL(int) RTSemMutexRequest(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies);
/**
* Request ownership of a mutex semaphore, return on interruption.
*
* This function will not resume the wait if interrupted.
*
* The same thread may request a mutex semaphore multiple times,
* a nested counter is kept to make sure it's released on the right
* RTSemMutexRelease() call.
*
* @returns iprt status code.
* @param hMutexSem The mutex semaphore to request ownership over.
* @param cMillies The number of milliseconds to wait.
*/
RTDECL(int) RTSemMutexRequestNoResume(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies);
/**
* Debug version of RTSemMutexRequest that tracks the location.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param hMutexSem The mutex semaphore to request ownership over.
* @param cMillies The number of milliseconds to wait.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemMutexRequestDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Debug version of RTSemMutexRequestNoResume that tracks the location.
*
* @returns iprt status code.
* @param hMutexSem The mutex semaphore to request ownership over.
* @param cMillies The number of milliseconds to wait.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemMutexRequestNoResumeDebug(RTSEMMUTEX hMutexSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Request ownership of a mutex semaphore, extended edition.
*
* The same thread may request a mutex semaphore multiple times,
* a nested counter is kept to make sure it's released on the right
* RTSemMutexRelease() call.
*
* @returns iprt status code.
* @param hMutexSem The mutex semaphore to request ownership over.
* @param fFlags Combination of the RTSEMWAIT_FLAGS_XXX.
* @param uTimeout The timeout, ignored if
* RTSEMWAIT_FLAGS_INDEFINITE is set in @a flags.
* Whether this is absolute or relative,
* milliseconds or nanoseconds depends on the @a
* fFlags value. Do not pass RT_INDEFINITE_WAIT
* here, use RTSEMWAIT_FLAGS_INDEFINITE instead.
*/
RTDECL(int) RTSemMutexRequestEx(RTSEMMUTEX hMutexSem, uint32_t fFlags, uint64_t uTimeout);
/**
* Debug version of RTSemMutexRequestEx that tracks the location.
*
* @returns iprt status code.
* @param hMutexSem The mutex semaphore to request ownership over.
* @param fFlags See RTSemMutexRequestEx.
* @param uTimeout See RTSemMutexRequestEx.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemMutexRequestExDebug(RTSEMMUTEX hMutexSem, uint32_t fFlags, uint64_t uTimeout,
RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Release the ownership of a mutex semaphore.
*
* @returns iprt status code.
* @param hMutexSem The mutex to release the ownership of. It goes
* without saying the the calling thread must own
* it.
*/
RTDECL(int) RTSemMutexRelease(RTSEMMUTEX hMutexSem);
/**
* Checks if the mutex semaphore is owned or not.
*
* @returns true if owned, false if not.
* @param hMutexSem The mutex semaphore.
*/
RTDECL(bool) RTSemMutexIsOwned(RTSEMMUTEX hMutexSem);
/* Strict build: Remap the two request calls to the debug versions. */
#if defined(RT_STRICT) && !defined(RTSEMMUTEX_WITHOUT_REMAPPING) && !defined(RT_WITH_MANGLING)
# ifdef IPRT_INCLUDED_asm_h
# define RTSemMutexRequest(hMutexSem, cMillies) RTSemMutexRequestDebug((hMutexSem), (cMillies), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# define RTSemMutexRequestNoResume(hMutexSem, cMillies) RTSemMutexRequestNoResumeDebug((hMutexSem), (cMillies), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# define RTSemMutexRequestEx(hMutexSem, fFlags, uTimeout) RTSemMutexRequestExDebug((hMutexSem), (fFlags), (uTimeout), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# else
# define RTSemMutexRequest(hMutexSem, cMillies) RTSemMutexRequestDebug((hMutexSem), (cMillies), 0, RT_SRC_POS)
# define RTSemMutexRequestNoResume(hMutexSem, cMillies) RTSemMutexRequestNoResumeDebug((hMutexSem), (cMillies), 0, RT_SRC_POS)
# define RTSemMutexRequestEx(hMutexSem, fFlags, uTimeout) RTSemMutexRequestExDebug((hMutexSem), (fFlags), (uTimeout), 0, RT_SRC_POS)
# endif
#endif
/* Strict lock order: Automatically classify locks by init location. */
#if defined(RT_LOCK_STRICT_ORDER) && defined(IN_RING3) && !defined(RTSEMMUTEX_WITHOUT_REMAPPING) && !defined(RT_WITH_MANGLING)
# define RTSemMutexCreate(phMutexSem) \
RTSemMutexCreateEx((phMutexSem), 0 /*fFlags*/, \
RTLockValidatorClassForSrcPos(RT_SRC_POS, NULL), \
RTLOCKVAL_SUB_CLASS_NONE, NULL)
#endif
/** @} */
/** @defgroup grp_rt_sems_fast_mutex RTSemFastMutex - Fast Mutex Semaphores
*
* Fast mutexes work like regular mutexes in that they allow only a single
* thread access to a critical piece of code or data. As opposed to mutexes,
* they require no syscall if the fast mutex is not held (like critical
* sections). Unlike critical sections however, they are *not* recursive.
*
* @remarks The fast mutexes has sideeffects on IRQL on Windows hosts. So use
* with care and test on windows with driver verifier.
*
* @{ */
/**
* Create a fast mutex semaphore.
*
* @returns iprt status code.
* @param phFastMtx Where to store the handle to the newly created
* fast mutex semaphore.
*
* @remarks Fast mutex semaphores are not recursive.
*/
RTDECL(int) RTSemFastMutexCreate(PRTSEMFASTMUTEX phFastMtx);
/**
* Destroy a fast mutex semaphore.
*
* @returns iprt status code.
* @param hFastMtx Handle to the fast mutex semaphore. NIL is
* quietly ignored (VINF_SUCCESS).
*/
RTDECL(int) RTSemFastMutexDestroy(RTSEMFASTMUTEX hFastMtx);
/**
* Request ownership of a fast mutex semaphore.
*
* The same thread may request a mutex semaphore multiple times,
* a nested counter is kept to make sure it's released on the right
* RTSemMutexRelease() call.
*
* @returns iprt status code.
* @param hFastMtx Handle to the fast mutex semaphore.
*/
RTDECL(int) RTSemFastMutexRequest(RTSEMFASTMUTEX hFastMtx);
/**
* Release the ownership of a fast mutex semaphore.
*
* @returns iprt status code.
* @param hFastMtx Handle to the fast mutex semaphore. It goes
* without saying the the calling thread must own
* it.
*/
RTDECL(int) RTSemFastMutexRelease(RTSEMFASTMUTEX hFastMtx);
/** @} */
/** @defgroup grp_rt_sems_spin_mutex RTSemSpinMutex - Spinning Mutex Semaphores
*
* A very adaptive variant of mutex semaphore that is tailored for the ring-0
* logger.
*
* @{ */
/**
* Creates a spinning mutex semaphore.
*
* @returns iprt status code.
* @retval VERR_INVALID_PARAMETER on invalid flags.
* @retval VERR_NO_MEMORY if out of memory for the semaphore structure and
* handle.
*
* @param phSpinMtx Where to return the handle to the create semaphore.
* @param fFlags Flags, see RTSEMSPINMUTEX_FLAGS_XXX.
*/
RTDECL(int) RTSemSpinMutexCreate(PRTSEMSPINMUTEX phSpinMtx, uint32_t fFlags);
/** @name RTSemSpinMutexCreate flags.
* @{ */
/** Always take the semaphore in a IRQ safe way.
* (In plain words: always disable interrupts.) */
#define RTSEMSPINMUTEX_FLAGS_IRQ_SAFE RT_BIT_32(0)
/** Mask of valid flags. */
#define RTSEMSPINMUTEX_FLAGS_VALID_MASK UINT32_C(0x00000001)
/** @} */
/**
* Destroys a spinning mutex semaphore.
*
* @returns iprt status code.
* @retval VERR_INVALID_HANDLE (or crash) if the handle is invalid. (NIL will
* not cause this status.)
*
* @param hSpinMtx The semaphore handle. NIL_RTSEMSPINMUTEX is ignored
* quietly (VINF_SUCCESS).
*/
RTDECL(int) RTSemSpinMutexDestroy(RTSEMSPINMUTEX hSpinMtx);
/**
* Request the spinning mutex semaphore.
*
* This may block if the context we're called in allows this. If not it will
* spin. If called in an interrupt context, we will only spin if the current
* owner isn't interrupted. Also, on some systems it is not always possible to
* wake up blocking threads in all contexts, so, which will either be indicated
* by returning VERR_SEM_BAD_CONTEXT or by temporarily switching the semaphore
* into pure spinlock state.
*
* Preemption will be disabled upon return. IRQs may also be disabled.
*
* @returns iprt status code.
* @retval VERR_SEM_BAD_CONTEXT if the context it's called in isn't suitable
* for releasing it if someone is sleeping on it.
* @retval VERR_SEM_DESTROYED if destroyed.
* @retval VERR_SEM_NESTED if held by the caller. Asserted.
* @retval VERR_INVALID_HANDLE if the handle is invalid. Asserted
*
* @param hSpinMtx The semaphore handle.
*/
RTDECL(int) RTSemSpinMutexRequest(RTSEMSPINMUTEX hSpinMtx);
/**
* Like RTSemSpinMutexRequest but it won't block or spin if the semaphore is
* held by someone else.
*
* @returns iprt status code.
* @retval VERR_SEM_BUSY if held by someone else.
* @retval VERR_SEM_DESTROYED if destroyed.
* @retval VERR_SEM_NESTED if held by the caller. Asserted.
* @retval VERR_INVALID_HANDLE if the handle is invalid. Asserted
*
* @param hSpinMtx The semaphore handle.
*/
RTDECL(int) RTSemSpinMutexTryRequest(RTSEMSPINMUTEX hSpinMtx);
/**
* Releases the semaphore previously acquired by RTSemSpinMutexRequest or
* RTSemSpinMutexTryRequest.
*
* @returns iprt status code.
* @retval VERR_SEM_DESTROYED if destroyed.
* @retval VERR_NOT_OWNER if not owner. Asserted.
* @retval VERR_INVALID_HANDLE if the handle is invalid. Asserted.
*
* @param hSpinMtx The semaphore handle.
*/
RTDECL(int) RTSemSpinMutexRelease(RTSEMSPINMUTEX hSpinMtx);
/** @} */
/** @defgroup grp_rt_sem_rw RTSemRW - Read / Write Semaphores
*
* Read/write semaphores are a fancier version of mutexes in that they grant
* read access to the protected data to several threads at the same time but
* allow only one writer at a time. This can make code scale better at the
* expense of slightly more overhead in mutex management.
*
* @{ */
/**
* Creates a read/write semaphore.
*
* @returns iprt status code.
* @param phRWSem Where to store the handle to the newly created
* RW semaphore.
*/
RTDECL(int) RTSemRWCreate(PRTSEMRW phRWSem);
/**
* Creates a read/write semaphore.
*
* @returns iprt status code.
* @param phRWSem Where to store the handle to the newly created
* RW semaphore.
* @param fFlags Flags, any combination of the RTSEMRW_FLAGS_XXX
* \#defines.
* @param hClass The class (no reference consumed). If NIL, no
* lock order validation will be performed on this
* lock.
* @param uSubClass The sub-class. This is used to define lock
* order within a class. RTLOCKVAL_SUB_CLASS_NONE
* is the recommended value here.
* @param pszNameFmt Name format string for the lock validator,
* optional (NULL). Max length is 32 bytes.
* @param ... Format string arguments.
*/
RTDECL(int) RTSemRWCreateEx(PRTSEMRW phRWSem, uint32_t fFlags, RTLOCKVALCLASS hClass, uint32_t uSubClass,
const char *pszNameFmt, ...) RT_IPRT_FORMAT_ATTR_MAYBE_NULL(5, 6);
/** @name RTSemRWCreateEx flags
* @{ */
/** Disables lock validation. */
#define RTSEMRW_FLAGS_NO_LOCK_VAL UINT32_C(0x00000001)
/** @} */
/**
* Destroys a read/write semaphore.
*
* @returns iprt status code.
* @param hRWSem Handle to the read/write semaphore. NIL is
* quietly ignored (VINF_SUCCESS).
*/
RTDECL(int) RTSemRWDestroy(RTSEMRW hRWSem);
/**
* Changes the lock validator sub-class of the read/write semaphore.
*
* It is recommended to try make sure that nobody is using this semaphore while
* changing the value.
*
* @returns The old sub-class. RTLOCKVAL_SUB_CLASS_INVALID is returns if the
* lock validator isn't compiled in or either of the parameters are
* invalid.
* @param hRWSem Handle to the read/write semaphore.
* @param uSubClass The new sub-class value.
*/
RTDECL(uint32_t) RTSemRWSetSubClass(RTSEMRW hRWSem, uint32_t uSubClass);
/**
* Request read access to a read/write semaphore, resume on interruption
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
*/
RTDECL(int) RTSemRWRequestRead(RTSEMRW hRWSem, RTMSINTERVAL cMillies);
/**
* Request read access to a read/write semaphore, return on interruption
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
*/
RTDECL(int) RTSemRWRequestReadNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies);
/**
* Debug version of RTSemRWRequestRead that tracks the location.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemRWRequestReadDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Debug version of RTSemRWRequestWriteNoResume that tracks the location.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemRWRequestReadNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Request read access to a read/write semaphore, extended edition.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_TIMEOUT if the wait timed out.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param fFlags Combination of the RTSEMWAIT_FLAGS_XXX.
* @param uTimeout The timeout, ignored if
* RTSEMWAIT_FLAGS_INDEFINITE is set in @a flags.
* Whether this is absolute or relative,
* milliseconds or nanoseconds depends on the @a
* fFlags value. Do not pass RT_INDEFINITE_WAIT
* here, use RTSEMWAIT_FLAGS_INDEFINITE instead.
*/
RTDECL(int) RTSemRWRequestReadEx(RTSEMRW hRWSem, uint32_t fFlags, uint64_t uTimeout);
/**
* Debug version of RTSemRWRequestReadEx that tracks the location.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_TIMEOUT if the wait timed out.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param fFlags See RTSemRWRequestReadEx.
* @param uTimeout See RTSemRWRequestReadEx.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemRWRequestReadExDebug(RTSEMRW hRWSem, uint32_t fFlags, uint64_t uTimeout,
RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Release read access to a read/write semaphore.
*
* @returns iprt status code.
* @param hRWSem Handle to the read/write semaphore. It goes
* without saying that caller must own read
* privileges to the semaphore.
*/
RTDECL(int) RTSemRWReleaseRead(RTSEMRW hRWSem);
/**
* Request write access to a read/write semaphore, resume on interruption.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_DEADLOCK if the caller owned the read lock.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
*/
RTDECL(int) RTSemRWRequestWrite(RTSEMRW hRWSem, RTMSINTERVAL cMillies);
/**
* Request write access to a read/write semaphore, return on interruption.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPT if the wait was interrupted.
* @retval VERR_DEADLOCK if the caller owned the read lock.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
*/
RTDECL(int) RTSemRWRequestWriteNoResume(RTSEMRW hRWSem, RTMSINTERVAL cMillies);
/**
* Debug version of RTSemRWRequestWrite that tracks the location.
*
* @returns IPRT status code, see RTSemRWRequestWrite.
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemRWRequestWriteDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Debug version of RTSemRWRequestWriteNoResume that tracks the location.
*
* @returns IPRT status code, see RTSemRWRequestWriteNoResume.
* @param hRWSem Handle to the read/write semaphore.
* @param cMillies The number of milliseconds to wait.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemRWRequestWriteNoResumeDebug(RTSEMRW hRWSem, RTMSINTERVAL cMillies, RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Request write access to a read/write semaphore, extended edition.
*
* @returns iprt status code.
* @retval VINF_SUCCESS on success.
* @retval VERR_INTERRUPTED if the wait was interrupted.
* @retval VERR_TIMEOUT if the wait timed out.
* @retval VERR_DEADLOCK if the caller owned the read lock. Do not depend on
* this as it is implementation specific.
* @retval VERR_INVALID_HANDLE if hRWSem is invalid.
*
* @param hRWSem Handle to the read/write semaphore.
* @param fFlags Combination of the RTSEMWAIT_FLAGS_XXX.
* @param uTimeout The timeout, ignored if
* RTSEMWAIT_FLAGS_INDEFINITE is set in @a flags.
* Whether this is absolute or relative,
* milliseconds or nanoseconds depends on the @a
* fFlags value. Do not pass RT_INDEFINITE_WAIT
* here, use RTSEMWAIT_FLAGS_INDEFINITE instead.
*/
RTDECL(int) RTSemRWRequestWriteEx(RTSEMRW hRWSem, uint32_t fFlags, uint64_t uTimeout);
/**
* Debug version of RTSemRWRequestWriteEx that tracks the location.
*
* @returns IPRT status code, see RTSemRWRequestWriteEx.
* @param hRWSem Handle to the read/write semaphore.
* @param fFlags See RTSemRWRequestWriteEx.
* @param uTimeout See RTSemRWRequestWriteEx.
* @param uId Some kind of locking location ID. Typically a
* return address up the stack. Optional (0).
* @param SRC_POS The source position where call is being made
* from. Use RT_SRC_POS when possible. Optional.
*/
RTDECL(int) RTSemRWRequestWriteExDebug(RTSEMRW hRWSem, uint32_t fFlags, uint64_t uTimeout,
RTHCUINTPTR uId, RT_SRC_POS_DECL);
/**
* Release write access to a read/write semaphore.
*
* @returns iprt status code.
* @param hRWSem Handle to the read/write semaphore. Goes
* without saying that caller must have write
* access to the semaphore.
*/
RTDECL(int) RTSemRWReleaseWrite(RTSEMRW hRWSem);
/**
* Checks if the caller is the exclusive semaphore owner.
*
* @returns true / false accoringly.
* @param hRWSem Handle to the read/write semaphore.
*/
RTDECL(bool) RTSemRWIsWriteOwner(RTSEMRW hRWSem);
/**
* Checks if the caller is one of the read owners of the semaphore.
*
* @note !CAUTION! This API doesn't work reliably if lock validation isn't
* enabled. Meaning, the answer is not trustworhty unless
* RT_LOCK_STRICT or RTSEMRW_STRICT was defined at build time. Also,
* make sure you do not use RTSEMRW_FLAGS_NO_LOCK_VAL when creating
* the semaphore. And finally, if you used a locking class, don't
* disable deadlock detection by setting cMsMinDeadlock to
* RT_INDEFINITE_WAIT.
*
* In short, only use this for assertions.
*
* @returns true if reader, false if not.
* @param hRWSem Handle to the read/write semaphore.
* @param fWannaHear What you'd like to hear when lock validation is
* not available. (For avoiding asserting all over
* the place.)
*/
RTDECL(bool) RTSemRWIsReadOwner(RTSEMRW hRWSem, bool fWannaHear);
/**
* Gets the write recursion count.
*
* @returns The write recursion count (0 if bad semaphore handle).
* @param hRWSem Handle to the read/write semaphore.
*/
RTDECL(uint32_t) RTSemRWGetWriteRecursion(RTSEMRW hRWSem);
/**
* Gets the read recursion count of the current writer.
*
* @returns The read recursion count (0 if bad semaphore handle).
* @param hRWSem Handle to the read/write semaphore.
*/
RTDECL(uint32_t) RTSemRWGetWriterReadRecursion(RTSEMRW hRWSem);
/**
* Gets the current number of reads.
*
* This includes all read recursions, so it might be higher than the number of
* read owners. It does not include reads done by the current writer.
*
* @returns The read count (0 if bad semaphore handle).
* @param hRWSem Handle to the read/write semaphore.
*/
RTDECL(uint32_t) RTSemRWGetReadCount(RTSEMRW hRWSem);
/* Strict build: Remap the four request calls to the debug versions. */
#if defined(RT_STRICT) && !defined(RTSEMRW_WITHOUT_REMAPPING) && !defined(RT_WITH_MANGLING)
# ifdef IPRT_INCLUDED_asm_h
# define RTSemRWRequestRead(hRWSem, cMillies) RTSemRWRequestReadDebug((hRWSem), (cMillies), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# define RTSemRWRequestReadNoResume(hRWSem, cMillies) RTSemRWRequestReadNoResumeDebug((hRWSem), (cMillies), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# define RTSemRWRequestWrite(hRWSem, cMillies) RTSemRWRequestWriteDebug((hRWSem), (cMillies), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# define RTSemRWRequestWriteNoResume(hRWSem, cMillies) RTSemRWRequestWriteNoResumeDebug((hRWSem), (cMillies), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# define RTSemRWRequestWriteEx(hRWSem, fFlags, uTimeout) RTSemRWRequestWriteExDebug((hRWSem), (fFlags), (uTimeout), (uintptr_t)ASMReturnAddress(), RT_SRC_POS)
# else
# define RTSemRWRequestRead(hRWSem, cMillies) RTSemRWRequestReadDebug((hRWSem), (cMillies), 0, RT_SRC_POS)
# define RTSemRWRequestReadNoResume(hRWSem, cMillies) RTSemRWRequestReadNoResumeDebug((hRWSem), (cMillies), 0, RT_SRC_POS)
# define RTSemRWRequestWrite(hRWSem, cMillies) RTSemRWRequestWriteDebug((hRWSem), (cMillies), 0, RT_SRC_POS)
# define RTSemRWRequestWriteNoResume(hRWSem, cMillies) RTSemRWRequestWriteNoResumeDebug((hRWSem), (cMillies), 0, RT_SRC_POS)
# define RTSemRWRequestWriteEx(hRWSem, fFlags, uTimeout) RTSemRWRequestWriteExDebug((hRWSem), (fFlags), (uTimeout), 0, RT_SRC_POS)
# endif
#endif
/* Strict lock order: Automatically classify locks by init location. */
#if defined(RT_LOCK_STRICT_ORDER) && defined(IN_RING3) && !defined(RTSEMRW_WITHOUT_REMAPPING) && !defined(RT_WITH_MANGLING)
# define RTSemRWCreate(phSemRW) \
RTSemRWCreateEx((phSemRW), 0 /*fFlags*/, \
RTLockValidatorClassForSrcPos(RT_SRC_POS, NULL), \
RTLOCKVAL_SUB_CLASS_NONE, NULL)
#endif
/** @} */
/** @defgroup grp_rt_sems_pingpong RTSemPingPong - Ping-Pong Construct
*
* Serialization of a two way communication.
*
* @{ */
/**
* Ping-pong speaker
*/
typedef enum RTPINGPONGSPEAKER
{
/** Not initialized. */
RTPINGPONGSPEAKER_UNINITIALIZE = 0,
/** Ping is speaking, Pong is waiting. */
RTPINGPONGSPEAKER_PING,
/** Pong is signaled, Ping is waiting. */
RTPINGPONGSPEAKER_PONG_SIGNALED,
/** Pong is speaking, Ping is waiting. */
RTPINGPONGSPEAKER_PONG,
/** Ping is signaled, Pong is waiting. */
RTPINGPONGSPEAKER_PING_SIGNALED,
/** Hack to ensure that it's at least 32-bits wide. */
RTPINGPONGSPEAKER_HACK = 0x7fffffff
} RTPINGPONGSPEAKER;
/**
* Ping-Pong construct.
*
* Two threads, one saying Ping and the other saying Pong. The construct
* makes sure they don't speak out of turn and that they can wait and poll
* on the conversation.
*/
typedef struct RTPINGPONG
{
/** The semaphore the Ping thread waits on. */
RTSEMEVENT Ping;
/** The semaphore the Pong thread waits on. */
RTSEMEVENT Pong;
/** The current speaker. */
volatile RTPINGPONGSPEAKER enmSpeaker;
#if HC_ARCH_BITS == 64
/** Padding the structure to become a multiple of sizeof(RTHCPTR). */
uint32_t u32Padding;
#endif
} RTPINGPONG;
/** Pointer to Ping-Pong construct. */
typedef RTPINGPONG *PRTPINGPONG;
/**
* Init a Ping-Pong construct.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure which needs initialization.
*/
RTDECL(int) RTSemPingPongInit(PRTPINGPONG pPP);
/**
* Deletes a Ping-Pong construct.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure which is to be destroyed.
* (I.e. put into uninitialized state.)
*/
RTDECL(int) RTSemPingPongDelete(PRTPINGPONG pPP);
/**
* Signals the pong thread in a ping-pong construct. (I.e. sends ping.)
* This is called by the ping thread.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure to ping.
*/
RTDECL(int) RTSemPing(PRTPINGPONG pPP);
/**
* Signals the ping thread in a ping-pong construct. (I.e. sends pong.)
* This is called by the pong thread.
*
* @returns iprt status code.
* @param pPP Pointer to the ping-pong structure to pong.
*/
RTDECL(int) RTSemPong(PRTPINGPONG pPP);
/**
* Wait function for the ping thread.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param pPP Pointer to the ping-pong structure to wait on.
* @param cMillies Number of milliseconds to wait.
*/
RTDECL(int) RTSemPingWait(PRTPINGPONG pPP, RTMSINTERVAL cMillies);
/**
* Wait function for the pong thread.
*
* @returns iprt status code.
* Will not return VERR_INTERRUPTED.
* @param pPP Pointer to the ping-pong structure to wait on.
* @param cMillies Number of milliseconds to wait.
*/
RTDECL(int) RTSemPongWait(PRTPINGPONG pPP, RTMSINTERVAL cMillies);
/**
* Checks if the pong thread is speaking.
*
* @returns true / false.
* @param pPP Pointer to the ping-pong structure.
* @remark This is NOT the same as !RTSemPongIsSpeaker().
*/
DECLINLINE(bool) RTSemPingIsSpeaker(PRTPINGPONG pPP)
{
RTPINGPONGSPEAKER enmSpeaker = pPP->enmSpeaker;
return enmSpeaker == RTPINGPONGSPEAKER_PING;
}
/**
* Checks if the pong thread is speaking.
*
* @returns true / false.
* @param pPP Pointer to the ping-pong structure.
* @remark This is NOT the same as !RTSemPingIsSpeaker().
*/
DECLINLINE(bool) RTSemPongIsSpeaker(PRTPINGPONG pPP)
{
RTPINGPONGSPEAKER enmSpeaker = pPP->enmSpeaker;
return enmSpeaker == RTPINGPONGSPEAKER_PONG;
}
/**
* Checks whether the ping thread should wait.
*
* @returns true / false.
* @param pPP Pointer to the ping-pong structure.
* @remark This is NOT the same as !RTSemPongShouldWait().
*/
DECLINLINE(bool) RTSemPingShouldWait(PRTPINGPONG pPP)
{
RTPINGPONGSPEAKER enmSpeaker = pPP->enmSpeaker;
return enmSpeaker == RTPINGPONGSPEAKER_PONG
|| enmSpeaker == RTPINGPONGSPEAKER_PONG_SIGNALED
|| enmSpeaker == RTPINGPONGSPEAKER_PING_SIGNALED;
}
/**
* Checks whether the pong thread should wait.
*
* @returns true / false.
* @param pPP Pointer to the ping-pong structure.
* @remark This is NOT the same as !RTSemPingShouldWait().
*/
DECLINLINE(bool) RTSemPongShouldWait(PRTPINGPONG pPP)
{
RTPINGPONGSPEAKER enmSpeaker = pPP->enmSpeaker;
return enmSpeaker == RTPINGPONGSPEAKER_PING
|| enmSpeaker == RTPINGPONGSPEAKER_PING_SIGNALED
|| enmSpeaker == RTPINGPONGSPEAKER_PONG_SIGNALED;
}
/** @} */
/** @defgroup grp_rt_sems_xroads RTSemXRoads - Crossroads
*
* The crossroads semaphore is intended to prevent two classes of incompatible
* events from occurring simultaneously, like south/north bound traffic and
* west/east bound traffic at a 4-way junction.
*
* @remarks In order to simplify the implementation, the current flow is always
* given priority. So, it won't work at all well when busy!
*
* @remarks "XRoads" is used as a name because it is briefer than "crossroads"
* and it slightly stresses that is a 4 way crossing to the users of
* American English.
* @{
*/
/**
* Creates a crossroads semaphore.
*
* @returns IPRT status code.
*
* @param phXRoads Where to return the handle to the newly created
* crossroads semaphore.
*/
RTDECL(int) RTSemXRoadsCreate(PRTSEMXROADS phXRoads);
/**
* Destroys a crossroads semaphore.
*
* @returns IPRT status code.
*
* @param hXRoads Handle to the crossroads semaphore that is to be
* destroyed. NIL_RTSEMXROADS is quitetly ignored
* (VINF_SUCCESS).
*/
RTDECL(int) RTSemXRoadsDestroy(RTSEMXROADS hXRoads);
/**
* Enter the crossroads from the south or north.
*
* (Coupled with RTSemXRoadsNSLeave.)
*
* @returns IPRT status code.
* @param hXRoads Handle to the crossroads semaphore.
*/
RTDECL(int) RTSemXRoadsNSEnter(RTSEMXROADS hXRoads);
/**
* Leave the crossroads to the north or south.
*
* (Coupled with RTSemXRoadsNSEnter.)
*
* @returns IPRT status code.
* @param hXRoads Handle to the crossroads semaphore.
*/
RTDECL(int) RTSemXRoadsNSLeave(RTSEMXROADS hXRoads);
/**
* Leave the crossroads from the east or west.
*
* (Coupled with RTSemXRoadsEWLeave.)
*
* @returns IPRT status code.
* @param hXRoads Handle to the crossroads semaphore.
*/
RTDECL(int) RTSemXRoadsEWEnter(RTSEMXROADS hXRoads);
/**
* Leave the crossroads to the west or east.
*
* (Coupled with RTSemXRoadsEWEnter.)
*
* @returns IPRT status code.
* @param hXRoads Handle to the crossroads semaphore.
*/
RTDECL(int) RTSemXRoadsEWLeave(RTSEMXROADS hXRoads);
/** @} */
/** @} */
RT_C_DECLS_END
#endif /* !IPRT_INCLUDED_semaphore_h */
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