/** @file * IPRT - Semaphore. */ /* * Copyright (C) 2006-2024 Oracle and/or its affiliates. * * This file is part of VirtualBox base platform packages, as * available from https://www.virtualbox.org. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, in version 3 of the * License. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included * in the VirtualBox 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. * * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 */ #ifndef IPRT_INCLUDED_semaphore_h #define IPRT_INCLUDED_semaphore_h #ifndef RT_WITHOUT_PRAGMA_ONCE # pragma once #endif #include #include #if defined(RT_LOCK_STRICT_ORDER) && defined(IN_RING3) # include #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); /** * Whether RTSemEventSignal can be safely called w/o risk of preemption. * * Checks whether the caller can safely signal a single release semaphore * without any risk of getting preempted on locks or similar while doing so. * This also checks whether the context is suitable in general. * * @returns true if safe, false if not. * @remarks Only ring-0. */ RTR0DECL(bool) RTSemEventIsSignalSafe(void); /** * 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); /** * Whether RTSemEventMultiSignal can be safely called w/o risk of preemption. * * Checks whether the caller can safely signal a multiple release semaphore * without any risk of getting preempted on locks or similar while doing so. * This also checks whether the context is suitable in general. * * @returns true if safe, false if not. * @remarks Only ring-0. */ RTR0DECL(bool) RTSemEventMultiIsSignalSafe(void); /** * 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 the driver verifier enabled. * * @{ */ /** * 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. * * @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 */