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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{
77 QSemaphore *m_sem = nullptr;
78 int m_n;
79public:
80 QSemaphoreReleaser() = default;
81 explicit QSemaphoreReleaser(QSemaphore &sem, int n = 1) Q_DECL_NOTHROW
82 : m_sem(&sem), m_n(n) {}
83 explicit QSemaphoreReleaser(QSemaphore *sem, int n = 1) Q_DECL_NOTHROW
84 : m_sem(sem), m_n(n) {}
85 QSemaphoreReleaser(QSemaphoreReleaser &&other) Q_DECL_NOTHROW
86 : m_sem(other.m_sem), m_n(other.m_n)
87 { other.m_sem = nullptr; }
88 QSemaphoreReleaser &operator=(QSemaphoreReleaser &&other) Q_DECL_NOTHROW
89 { QSemaphoreReleaser moved(std::move(other)); swap(moved); return *this; }
90
91 ~QSemaphoreReleaser()
92 {
93 if (m_sem)
94 m_sem->release(m_n);
95 }
96
97 void swap(QSemaphoreReleaser &other) Q_DECL_NOTHROW
98 {
99 qSwap(m_sem, other.m_sem);
100 qSwap(m_n, other.m_n);
101 }
102
103 QSemaphore *semaphore() const Q_DECL_NOTHROW
104 { return m_sem; }
105
106 QSemaphore *cancel() Q_DECL_NOTHROW
107 {
108 QSemaphore *old = m_sem;
109 m_sem = nullptr;
110 return old;
111 }
112};
113
114#endif // QT_NO_THREAD
115
116QT_END_NAMESPACE
117
118#endif // QSEMAPHORE_H
119