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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
//! [0]
int number = 6;
void method1()
{
number *= 5;
number /= 4;
}
void method2()
{
number *= 3;
number /= 2;
}
//! [0]
//! [1]
// method1()
number *= 5; // number is now 30
number /= 4; // number is now 7
// method2()
number *= 3; // number is now 21
number /= 2; // number is now 10
//! [1]
//! [2]
// Thread 1 calls method1()
number *= 5; // number is now 30
// Thread 2 calls method2().
//
// Most likely Thread 1 has been put to sleep by the operating
// system to allow Thread 2 to run.
number *= 3; // number is now 90
number /= 2; // number is now 45
// Thread 1 finishes executing.
number /= 4; // number is now 11, instead of 10
//! [2]
//! [3]
QMutex mutex;
int number = 6;
void method1()
{
mutex.lock();
number *= 5;
number /= 4;
mutex.unlock();
}
void method2()
{
mutex.lock();
number *= 3;
number /= 2;
mutex.unlock();
}
//! [3]
//! [4]
int complexFunction(int flag)
{
mutex.lock();
int retVal = 0;
switch (flag) {
case 0:
case 1:
retVal = moreComplexFunction(flag);
break;
case 2:
{
int status = anotherFunction();
if (status < 0) {
mutex.unlock();
return -2;
}
retVal = status + flag;
}
break;
default:
if (flag > 10) {
mutex.unlock();
return -1;
}
break;
}
mutex.unlock();
return retVal;
}
//! [4]
//! [5]
int complexFunction(int flag)
{
QMutexLocker locker(&mutex);
int retVal = 0;
switch (flag) {
case 0:
case 1:
return moreComplexFunction(flag);
case 2:
{
int status = anotherFunction();
if (status < 0)
return -2;
retVal = status + flag;
}
break;
default:
if (flag > 10)
return -1;
break;
}
return retVal;
}
//! [5]
//! [6]
class SignalWaiter
{
private:
QMutexLocker<QMutex> locker;
public:
SignalWaiter(QMutex *mutex)
: locker(mutex)
{
}
void waitForSignal()
{
...
while (!signalled)
waitCondition.wait(locker.mutex());
...
}
};
//! [6]
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