bsls_bsllockimpl_pthread.h

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/// @file bsls_bsllockimpl_pthread.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bsls_bsllockimpl_pthread.h                                         -*-C++-*-
#ifndef INCLUDED_BSLS_BSLLOCKIMPL_PTHREAD
#define INCLUDED_BSLS_BSLLOCKIMPL_PTHREAD
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bsls_bsllockimpl_pthread bsls_bsllockimpl_pthread
/// @brief  Provide a mutex for use below `bslmt`.
/// @addtogroup bsl
/// @{
/// @addtogroup bsls
/// @{
/// @addtogroup bsls_bsllockimpl_pthread
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bsls_bsllockimpl_pthread-purpose"> Purpose</a>
/// * <a href="#bsls_bsllockimpl_pthread-classes"> Classes </a>
/// * <a href="#bsls_bsllockimpl_pthread-description"> Description </a>
///   * <a href="#bsls_bsllockimpl_pthread-usage"> Usage </a>
///
/// # Purpose {#bsls_bsllockimpl_pthread-purpose}
/// Provide a mutex for use below `bslmt`.
///
/// # Classes {#bsls_bsllockimpl_pthread-classes}
///
/// -  bsls::BslLockImpl_pthread: pthread mutex
///
/// @see  bslmt_mutex
///
/// # Description {#bsls_bsllockimpl_pthread-description}
/// This component provides a mutually exclusive lock primitive
/// ("mutex") by wrapping a suitable platform-specific mechanism.  The
/// `bsls::BslLockImpl_pthread` class provides `lock` and `unlock` operations.
/// Note that `bsls::BslLockImpl_pthread` is not intended for direct client use;
/// see @ref bslmt_mutex  instead.  Also note that `bsls::BslLockImpl_pthread` is
/// not recursive.
///
/// ## Usage {#bsls_bsllockimpl_pthread-usage}
///
///
/// This component is an implementation detail of `bsls` and is *not* intended
/// for direct client use.  It is subject to change without notice.  As such, a
/// usage example is not provided.
/// @}
/** @} */
/** @} */
 
/** @addtogroup bsl
 * @{
 */
/** @addtogroup bsls
 * @{
 */
/** @addtogroup bsls_bsllockimpl_pthread
 * @{
 */
 
#include <bsls_buildtarget.h>
#include <bsls_platform.h>
 
#ifdef BSLS_PLATFORM_OS_UNIX
 
#include <pthread.h>
 
#ifdef BDE_BUILD_TARGET_SAFE
// This component needs to be below bsls_assert in the physical hierarchy, so
// 'BSLS_ASSERT' macros can't be used here.  To workaround this issue, we use
// the C 'assert' instead.
 
#include <assert.h>
 
#define BSLS_BSLLOCKIMPL_PTHREAD_ASSERT_SAFE(x) assert((x))
#else
#define BSLS_BSLLOCKIMPL_PTHREAD_ASSERT_SAFE(x)
#endif
 
 
namespace bsls {
 
                              // =========================
                              // class BslLockImpl_pthread
                              // =========================
 
/// This `class` implements a light-weight wrapper of an OS-level mutex to
/// support intra-process synchronization.  The mutex implemented by this class is *non*-recursive.  
/// 
/// \note Note that   `BslLockImpl_pthread` is *not*
/// intended for direct use by client code; it is meant for internal use
/// only.
///
/// See @ref bsls_bsllockimpl_pthread 
class BslLockImpl_pthread {
 
    // DATA
    pthread_mutex_t  d_lock;  // 'pthreads' mutex object
 
  private:
    // NOT IMPLEMENTED
    BslLockImpl_pthread(const BslLockImpl_pthread&);             // = delete
    BslLockImpl_pthread& operator=(const BslLockImpl_pthread&);  // = delete
 
  public:
    // CREATORS
 
    /// Create a lock object initialized to the unlocked state.
    BslLockImpl_pthread();
 
    /// Destroy this lock object.  
    /// \pre The behavior is undefined  unless this
    /// object is in the unlocked state.
    ~BslLockImpl_pthread();
 
    // MANIPULATORS
 
    /// Acquire the lock on this object.  If the lock on this object is
    /// currently held by another thread, then suspend execution of the
    /// calling thread until the lock can be acquired.  
    /// 
    /// \pre The behavior is undefined   unless the calling thread does not already hold the lock on this object.  
    /// 
    /// \note Note that   deadlock may result if this method is
    /// invoked while the calling thread holds the lock on the object.
    void lock();
 
    /// Release the lock on this object that was previously acquired through
    /// a call to `lock`, enabling another thread to acquire the lock.  
    /// 
    /// \pre The behavior is undefined   unless the calling thread holds the lock on
    /// this object.
    void unlock();
};
 
// ============================================================================
//                        INLINE FUNCTION DEFINITIONS
// ============================================================================
 
                              // -------------------------
                              // class BslLockImpl_pthread
                              // -------------------------
 
// CREATORS
inline
BslLockImpl_pthread::BslLockImpl_pthread()
{
    const int status = pthread_mutex_init(&d_lock, 0);
    (void)status;
    BSLS_BSLLOCKIMPL_PTHREAD_ASSERT_SAFE(0 == status);
}
 
inline
BslLockImpl_pthread::~BslLockImpl_pthread()
{
    const int status = pthread_mutex_destroy(&d_lock);
    (void)status;
    BSLS_BSLLOCKIMPL_PTHREAD_ASSERT_SAFE(0 == status);
}
 
// MANIPULATORS
inline
void BslLockImpl_pthread::lock()
{
    const int status = pthread_mutex_lock(&d_lock);
    (void)status;
    BSLS_BSLLOCKIMPL_PTHREAD_ASSERT_SAFE(0 == status);
}
 
inline
void BslLockImpl_pthread::unlock()
{
    const int status = pthread_mutex_unlock(&d_lock);
    (void)status;
    BSLS_BSLLOCKIMPL_PTHREAD_ASSERT_SAFE(0 == status);
}
 
 
}  // close package namespace
 
 
#endif  // BSLS_PLATFORM_OS_UNIX
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2021 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */