分享一些Qt实用函数(宏)

template <typename T>
Q_DECL_CONSTEXPR inline T qAbs(const T &t) { return t >= 0 ? t : -t; }

Q_DECL_CONSTEXPR inline int qRound(double d)
{ return d >= 0.0 ? int(d + 0.5) : int(d - double(int(d-1)) + 0.5) + int(d-1); }
Q_DECL_CONSTEXPR inline int qRound(float d)
{ return d >= 0.0f ? int(d + 0.5f) : int(d - float(int(d-1)) + 0.5f) + int(d-1); }

Q_DECL_CONSTEXPR inline qint64 qRound64(double d)
{ return d >= 0.0 ? qint64(d + 0.5) : qint64(d - double(qint64(d-1)) + 0.5) + qint64(d-1); }
Q_DECL_CONSTEXPR inline qint64 qRound64(float d)
{ return d >= 0.0f ? qint64(d + 0.5f) : qint64(d - float(qint64(d-1)) + 0.5f) + qint64(d-1); }

template <typename T>
Q_DECL_CONSTEXPR inline const T &qMin(const T &a, const T &b) { return (a < b) ? a : b; }
template <typename T>
Q_DECL_CONSTEXPR inline const T &qMax(const T &a, const T &b) { return (a < b) ? b : a; }

template <typename T>
Q_DECL_CONSTEXPR inline const T &qBound(const T &min, const T &val, const T &max)
{ return qMax(min, qMin(max, val)); }

#define QT_STRINGIFY2(x) #x
#define QT_STRINGIFY(x) QT_STRINGIFY2(x)

#define Q_UNUSED(x) (void)x;

#define Q_DISABLE_COPY(Class) \
    Class(const Class &) Q_DECL_EQ_DELETE;\
    Class &operator=(const Class &) Q_DECL_EQ_DELETE;

Q_CORE_EXPORT bool qputenv(const char *varName, const QByteArray& value);

Q_CORE_EXPORT QByteArray qgetenv(const char *varName);

Q_CORE_EXPORT void qsrand(uint seed);
Q_CORE_EXPORT int qrand();

#define Q_FOREVER for(;;)

#define Q_D(Class) Class##Private * const d = d_func()
#define Q_Q(Class) Class * const q = q_func()