qglobal.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

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**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtCore module of the Qt Toolkit.
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#include "qplatformdefs.h"
#include "qstring.h"

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <stdarg.h>
#include <errno.h>

#if defined(Q_CC_MSVC) && !defined(Q_OS_TEMP)
#include <crtdbg.h>
#endif

/*!
    \class QFlag
    \brief The QFlag class is a helper data type for QFlags.

    It is equivalent to a plain \c int, except with respect to
    function overloading and type conversions. You should never need
    to use this class in your applications.

    \sa QFlags
*/

/*!
    \fn QFlag::QFlag(int value)

    Constructs a QFlag object that stores the given \a value.
*/

/*!
    \fn QFlag::operator int() const

    Returns the value stored by the QFlag object.
*/

/*!
    \class QFlags
    \brief The QFlags class provides a type-safe way of storing
    OR-combinations of enum values.

    \mainclass
    \ingroup tools

    The QFlags<Enum> class is a template class, where Enum is an enum
    type. QFlags is used throughout Qt for storing combinations of
    enum values.

    The traditional C++ approach for storing OR-combinations of enum
    values is to use an \c int or \c uint variable. The inconvenience
    with this approach is that there's no type checking at all; any
    enum value can be OR'd with any other enum value and passed on to
    a function that takes an \c int or \c uint.

    Qt uses QFlags to provide type safety. For example, the
    Qt::Alignment type is simply a typedef for
    QFlags<Qt::AlignmentFlag>. QLabel::setAlignment() takes a
    Qt::Alignment parameter, which means that any combination of
    Qt::AlignmentFlag values is legal:

    \code
        label->setAlignment(Qt::AlignLeft | Qt::AlignTop);
    \endcode

    If you try to pass a value from another enum, the compiler will
    report an error.

    If you want to use QFlags for your own enum types, use
    the Q_DECLARE_FLAGS() and Q_DECLARE_OPERATORS_FOR_FLAGS().
    For example:

    \code
        class MyClass
        {
        public:
            enum Option {
                NoOptions = 0x0,
                ShowTabs = 0x1,
                ShowAll = 0x2,
                SqueezeBlank = 0x4
            };
            Q_DECLARE_FLAGS(Options, Option)
            ...
        };

        Q_DECLARE_OPERATORS_FOR_FLAGS(MyClass::Options)
    \endcode

    You can then use the \c MyClass::Options type to store
    combinations of \c MyClass::Option values.

    A sensible naming convension for enum types and associated QFlags
    types is to give a singular name to the enum type (e.g., \c
    Option) and a plural name to the QFlags type (e.g., \c Options).
    When a singular name is desired for the QFlags type (e.g., \c
    Alignment), you can use \c Flag as the suffix for the enum type
    (e.g., \c AlignmentFlag).

    \sa QFlag
*/

/*!
    \typedef QFlags::enum_type

    Typedef for the Enum template type.
*/

/*!
    \fn QFlags::QFlags(const QFlags &other)

    Constructs a copy of \a other.
*/

/*!
    \fn QFlags::QFlags(Enum flag)

    Constructs a QFlags object storing the given \a flag.
*/

/*!
    \fn QFlags::QFlags(Zero zero)

    Constructs a QFlags object with no flags set. \a zero must be a
    literal 0 value.
*/

/*!
    \fn QFlags::QFlags(QFlag value)

    Constructs a QFlags object initialized with the given integer \a
    value.

    The QFlag type is a helper type. By using it here instead of \c
    int, we effectively ensure that arbitrary enum values cannot be
    cast to a QFlags, whereas untyped enum values (i.e., \c int
    values) can.
*/

/*!
    \fn QFlags &QFlags::operator=(const QFlags &other)

    Assigns \a other to this object and returns a reference to this
    object.
*/

/*!
    \fn QFlags &QFlags::operator&=(int mask)

    Performs a bitwise AND operation with \a mask and stores the
    result in this QFlags object. Returns a reference to this object.

    \sa operator&(), operator|=(), operator^=()
*/

/*!
    \fn QFlags &QFlags::operator&=(uint mask)

    \overload
*/

/*!
    \fn QFlags &QFlags::operator|=(QFlags other)

    Performs a bitwise OR operation with \a other and stores the
    result in this QFlags object. Returns a reference to this object.

    \sa operator|(), operator&=(), operator^=()
*/

/*!
    \fn QFlags &QFlags::operator|=(Enum other)

    \overload
*/

/*!
    \fn QFlags &QFlags::operator^=(QFlags other)

    Performs a bitwise XOR operation with \a other and stores the
    result in this QFlags object. Returns a reference to this object.

    \sa operator^(), operator&=(), operator|=()
*/

/*!
    \fn QFlags &QFlags::operator^=(Enum other)

    \overload
*/

/*!
    \fn QFlags::operator int() const

    Returns the value stored in the QFlags object as an integer.
*/

/*!
    \fn QFlags QFlags::operator|(QFlags other) const

    Returns a QFlags object containing the result of the bitwise OR
    operation on this object and \a other.

    \sa operator|=(), operator^(), operator&(), operator~()
*/

/*!
    \fn QFlags QFlags::operator|(Enum other) const

    \overload
*/

/*!
    \fn QFlags QFlags::operator^(QFlags other) const

    Returns a QFlags object containing the result of the bitwise XOR
    operation on this object and \a other.

    \sa operator^=(), operator&(), operator|(), operator~()
*/

/*!
    \fn QFlags QFlags::operator^(Enum other) const

    \overload
*/

/*!
    \fn QFlags QFlags::operator&(int mask) const

    Returns a QFlags object containing the result of the bitwise AND
    operation on this object and \a mask.

    \sa operator&=(), operator|(), operator^(), operator~()
*/

/*!
    \fn QFlags QFlags::operator&(uint mask) const

    \overload
*/

/*!
    \fn QFlags QFlags::operator&(Enum mask) const

    \overload
*/

/*!
    \fn QFlags QFlags::operator~() const

    Returns a QFlags object that contains the bitwise negation of
    this object.

    \sa operator&(), operator|(), operator^()
*/

/*!
    \fn bool QFlags::operator!() const

    Returns true if no flag is set (i.e., if the value stored by the
    QFlags object is 0); otherwise returns false.
*/

/*!
    \macro Q_DECLARE_FLAGS(Flags, Enum)
    \relates QFlags

    The Q_DECLARE_FLAGS() macro expands to

    \code
        typedef QFlags<Enum> Flags;
    \endcode

    \a Enum is the name of an existing enum type, whereas \a Flags is
    the name of the QFlags<\e{Enum}> typedef.

    See the QFlags documentation for details.

    \sa Q_DECLARE_OPERATORS_FOR_FLAGS()
*/

/*!
    \macro Q_DECLARE_OPERATORS_FOR_FLAGS(Flags)
    \relates QFlags

    The Q_DECLARE_OPERATORS_FOR_FLAGS() macro declares global \c
    operator|() functions for \a Flags, which is of type QFlags<T>.

    See the QFlags documentation for details.

    \sa Q_DECLARE_FLAGS()
*/

/*!
    \headerfile <QtGlobal>
    \title Global Qt Declarations

    \brief The <QtGlobal> header file provides basic declarations and
    is included by all other Qt headers.

    The declarations include \l {types}, \l functions and
    \l macros.

    The type definitions are partly convenience definitions for basic
    types (some of which guarantee certain bit-sizes on all platforms
    supported by Qt), partly types related to Qt message handling. The
    functions are related to generating messages, Qt version handling
    and comparing and adjusting object values. And finally, some of
    the declared macros enable programmers to add compiler or platform
    specific code to their applications, while others are convenience
    macros for larger operations.

    \section1 Types

    The header file declares several type definitions that guarantee a
    specified bit-size on all platforms supported by Qt for various
    basic types, for example \l qint8 which is a signed char
    guaranteed to be 8-bit on all platforms supported by Qt. The
    header file also declares the \l qlonglong type definition for \c
    {long long int } (\c __int64 on Windows).

    Several convenience type definitions are declared: \l qreal for \c
    double, \l uchar for \c unsigned char, \l uint for \c unsigned
    int, \l ulong for \c unsigned long and \l ushort for \c unsigned
    short.

    Finally, the QtMsgType definition identifies the various messages
    that can be generated and sent to a Qt message handler;
    QtMsgHandler is a type definition for a pointer to a function with
    the signature \c {void myMsgHandler(QtMsgType, const char *)}.

    \section1 Functions

    The <QtGlobal> header file contains several functions comparing
    and adjusting an object's value. These functions take a template
    type as argument: You can retrieve the absolute value of an object
    using the qAbs() function, and you can bound a given object's
    value by given minimum and maximum values using the qBound()
    function. You can retrieve the minimum and maximum of two given
    objects using qMin() and qMax() respectively. All these functions
    return a corresponding template type; the template types can be
    replaced by any other type. For example:

    \code
        int myValue = 10;
        int minValue = 2;
        int maxValue = 6;

        int boundedValue = qBound(minValue, myValue, maxValue);
        // boundedValue == 6
    \endcode

    <QtGlobal> also contains functions that generate messages from the
    given string argument: qCritical(), qDebug(), qFatal() and
    qWarning(). These functions call the message handler with the
    given message. For example:

    \code
        if (!driver()->isOpen() || driver()->isOpenError()) {
            qWarning("QSqlQuery::exec: database not open");
            return false;
        }
    \endcode

    The remaining functions are qRound() and qRound64(), which both
    accept a \l qreal value as their argument returning the value
    rounded up to the nearest integer and 64-bit integer respectively,
    the qInstallMsgHandler() function which installs the given
    QtMsgHandler, and the qVersion() function which returns the
    version number of Qt at run-time as a string.

    \section1 Macros

    The <QtGlobal> header file provides a range of macros (Q_CC_*)
    that are defined if the application is compiled using the
    specified platforms. For example, the Q_CC_SUN macro is defined if
    the application is compiled using Forte Developer, or Sun Studio
    C++.  The header file also declares a range of macros (Q_OS_*)
    that are defined for the specified platforms. For example,
    Q_OS_X11 which is defined for the X Window System.

    The purpose of these macros is to enable programmers to add
    compiler or platform specific code to their application.

    The remaining macros are convenience macros for larger operations:
    The QT_TRANSLATE_NOOP() and QT_TR_NOOP() macros provide the
    possibility of marking text for dynamic translation,
    i.e. translation without changing the stored source text. The
    Q_ASSERT() and Q_ASSERT_X() enables warning messages of various
    level of refinement. The Q_FOREACH() and foreach() macros
    implement Qt's foreach loop.

    The Q_INT64_C() and Q_UINT64_C() macros wrap signed and unsigned
    64-bit integer literals in a platform-independent way. The
    Q_CHECK_PTR() macro prints a warning containing the source code's
    file name and line number, saying that the program ran out of
    memory, if the pointer is 0. The qPrintable() macro represent an
    easy way of printing text.

    Finally, the QT_POINTER_SIZE macro expands to the size of a
    pointer in bytes, and the QT_VERSION and QT_VERSION_STR macros
    expand to a numeric value or a string, respectively, specifying
    Qt's version number, i.e the version the application is compiled
    against.

    \sa <QtAlgorithms>, QSysInfo
*/

/*!
    \typedef qreal
    \relates <QtGlobal>

    Typedef for \c double.
*/

/*! \typedef uchar
    \relates <QtGlobal>

    Convenience typedef for \c{unsigned char}.
*/

/*! \typedef ushort
    \relates <QtGlobal>

    Convenience typedef for \c{unsigned short}.
*/

/*! \typedef uint
    \relates <QtGlobal>

    Convenience typedef for \c{unsigned int}.
*/

/*! \typedef ulong
    \relates <QtGlobal>

    Convenience typedef for \c{unsigned long}.
*/

/*! \typedef qint8
    \relates <QtGlobal>

    Typedef for \c{signed char}. This type is guaranteed to be 8-bit
    on all platforms supported by Qt.
*/

/*!
    \typedef quint8
    \relates <QtGlobal>

    Typedef for \c{unsigned char}. This type is guaranteed to
    be 8-bit on all platforms supported by Qt.
*/

/*! \typedef qint16
    \relates <QtGlobal>

    Typedef for \c{signed short}. This type is guaranteed to be
    16-bit on all platforms supported by Qt.
*/

/*!
    \typedef quint16
    \relates <QtGlobal>

    Typedef for \c{unsigned short}. This type is guaranteed to
    be 16-bit on all platforms supported by Qt.
*/

/*! \typedef qint32
    \relates <QtGlobal>

    Typedef for \c{signed int}. This type is guaranteed to be 32-bit
    on all platforms supported by Qt.
*/

/*!
    \typedef quint32
    \relates <QtGlobal>

    Typedef for \c{unsigned int}. This type is guaranteed to
    be 32-bit on all platforms supported by Qt.
*/

/*! \typedef qint64
    \relates <QtGlobal>

    Typedef for \c{long long int} (\c __int64 on Windows). This type
    is guaranteed to be 64-bit on all platforms supported by Qt.

    Literals of this type can be created using the Q_INT64_C() macro:

    \code
        qint64 value = Q_INT64_C(932838457459459);
    \endcode

    \sa Q_INT64_C(), quint64, qlonglong
*/

/*!
    \typedef quint64
    \relates <QtGlobal>

    Typedef for \c{unsigned long long int} (\c{unsigned __int64} on
    Windows). This type is guaranteed to be 64-bit on all platforms
    supported by Qt.

    Literals of this type can be created using the Q_UINT64_C()
    macro:

    \code
        quint64 value = Q_UINT64_C(932838457459459);
    \endcode

    \sa Q_UINT64_C(), qint64, qulonglong
*/

/*!
    \typedef QtMsgHandler
    \relates <QtGlobal>

    This is a typedef for a pointer to a function with the following
    signature:

    \code
        void myMsgHandler(QtMsgType, const char *);
    \endcode

    \sa QtMsgType, qInstallMsgHandler()
*/

/*!
    \enum QtMsgType
    \relates <QtGlobal>

    This enum describes the messages that can be sent to a message
    handler (QtMsgHandler). You can use the enum to identify and
    associate the various message types with the appropiate
    actions.

    \value QtDebugMsg
           A message generated by the qDebug() function.
    \value QtWarningMsg
           A message generated by the qWarning() function.
    \value QtCriticalMsg
           A message generated by the qCritical() function.
    \value QtFatalMsg
           A message generated by the qFatal() function.
    \value QtSystemMsg


    \sa QtMsgHandler, qInstallMsgHandler()
*/

/*! \macro qint64 Q_INT64_C(literal)
    \relates <QtGlobal>

    Wraps the signed 64-bit integer \a literal in a
    platform-independent way. For example:

    \code
        qint64 value = Q_INT64_C(932838457459459);
    \endcode

    \sa qint64, Q_UINT64_C()
*/

/*! \macro quint64 Q_UINT64_C(literal)
    \relates <QtGlobal>

    Wraps the unsigned 64-bit integer \a literal in a
    platform-independent way. For example:

    \code
        quint64 value = Q_UINT64_C(932838457459459);
    \endcode

    \sa quint64, Q_INT64_C()
*/

/*! \typedef qlonglong
    \relates <QtGlobal>

    Typedef for \c{long long int} (\c __int64 on Windows). This is
    the same as \l qint64.

    \sa qulonglong, qint64
*/

/*!
    \typedef qulonglong
    \relates <QtGlobal>

    Typedef for \c{unsigned long long int} (\c{unsigned __int64} on
    Windows). This is the same as \l quint64.

    \sa quint64, qlonglong