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39
40#ifndef QSEMAPHORE_H
41#define QSEMAPHORE_H
42
43#include <QtCore/qglobal.h>
44
45QT_BEGIN_NAMESPACE
46
47
48#ifndef QT_NO_THREAD
49
50class QSemaphorePrivate;
51
52class Q_CORE_EXPORT QSemaphore
53{
54public:
55 explicit QSemaphore(int n = 0);
56 ~QSemaphore();
57
58 void acquire(int n = 1);
59 bool tryAcquire(int n = 1);
60 bool tryAcquire(int n, int timeout);
61
62 void release(int n = 1);
63
64 int available() const;
65
66private:
67 Q_DISABLE_COPY(QSemaphore)
68
69 union {
70 QSemaphorePrivate *d;
71 QBasicAtomicInteger<quintptr> u; // ### Qt6: make 64-bit
72 };
73};
74
75class QSemaphoreReleaser
76{
77public:
78 QSemaphoreReleaser() = default;
79 explicit QSemaphoreReleaser(QSemaphore &sem, int n = 1) Q_DECL_NOTHROW
80 : m_sem(&sem), m_n(n) {}
81 explicit QSemaphoreReleaser(QSemaphore *sem, int n = 1) Q_DECL_NOTHROW
82 : m_sem(sem), m_n(n) {}
83 QSemaphoreReleaser(QSemaphoreReleaser &&other) Q_DECL_NOTHROW
84 : m_sem(other.m_sem), m_n(other.m_n)
85 { other.m_sem = nullptr; }
86 QSemaphoreReleaser &operator=(QSemaphoreReleaser &&other) Q_DECL_NOTHROW
87 { QSemaphoreReleaser moved(std::move(other)); swap(moved); return *this; }
88
89 ~QSemaphoreReleaser()
90 {
91 if (m_sem)
92 m_sem->release(m_n);
93 }
94
95 void swap(QSemaphoreReleaser &other) Q_DECL_NOTHROW
96 {
97 qSwap(m_sem, other.m_sem);
98 qSwap(m_n, other.m_n);
99 }
100
101 QSemaphore *semaphore() const Q_DECL_NOTHROW
102 { return m_sem; }
103
104 QSemaphore *cancel() Q_DECL_NOTHROW
105 {
106 QSemaphore *old = m_sem;
107 m_sem = nullptr;
108 return old;
109 }
110
111private:
112 QSemaphore *m_sem = nullptr;
113 int m_n;
114};
115
116#endif // QT_NO_THREAD
117
118QT_END_NAMESPACE
119
120#endif // QSEMAPHORE_H
121