QProcessEnvironment Class Reference

The QProcessEnvironment class holds the environment variables that can be passed to a program. More...

#include <qprocess.h>

Public Functions
void	clear ()
	Removes all key=value pairs from this QProcessEnvironment object, making it empty. More...
bool	contains (const QString &name) const
	Returns true if the environment variable of name name is found in this QProcessEnvironment object. More...
void	insert (const QString &name, const QString &value)
	Inserts the environment variable of name name and contents value into this QProcessEnvironment object. More...
void	insert (const QProcessEnvironment &e)
	Inserts the contents of e in this QProcessEnvironment object. More...
bool	isEmpty () const
	Returns true if this QProcessEnvironment object is empty: that is there are no key=value pairs set. More...
QStringList	keys () const
	Returns a list containing all the variable names in this QProcessEnvironment object. More...
bool	operator!= (const QProcessEnvironment &other) const
	Returns true if this and the other QProcessEnvironment objects are different. More...
QProcessEnvironment &	operator= (const QProcessEnvironment &other)
	Copies the contents of the other QProcessEnvironment object into this one. More...
bool	operator== (const QProcessEnvironment &other) const
	Returns true if this and the other QProcessEnvironment objects are equal. More...
	QProcessEnvironment ()
	Creates a new QProcessEnvironment object. More...
	QProcessEnvironment (const QProcessEnvironment &other)
	Creates a QProcessEnvironment object that is a copy of other. More...
void	remove (const QString &name)
	Removes the environment variable identified by name from this QProcessEnvironment object. More...
QStringList	toStringList () const
	Converts this QProcessEnvironment object into a list of strings, one for each environment variable that is set. More...
QString	value (const QString &name, const QString &defaultValue=QString()) const
	Searches this QProcessEnvironment object for a variable identified by name and returns its value. More...
	~QProcessEnvironment ()
	Frees the resources associated with this QProcessEnvironment object. More...

Static Public Functions
static QProcessEnvironment	systemEnvironment ()
	The systemEnvironment function returns the environment of the calling process. More...

Properties
QSharedDataPointer< QProcessEnvironmentPrivate >	d

Friends
class	QProcessEnvironmentPrivate
class	QProcessPrivate

Detailed Description

The QProcessEnvironment class holds the environment variables that can be passed to a program.

Note

This class or function is reentrant.

Since

4.6

A process's environment is composed of a set of key=value pairs known as environment variables. The QProcessEnvironment class wraps that concept and allows easy manipulation of those variables. It's meant to be used along with QProcess, to set the environment for child processes. It cannot be used to change the current process's environment.

The environment of the calling process can be obtained using QProcessEnvironment::systemEnvironment().

On Unix systems, the variable names are case-sensitive. For that reason, this class will not touch the names of the variables. Note as well that Unix environment allows both variable names and contents to contain arbitrary binary data (except for the NUL character), but this is not supported by QProcessEnvironment. This class only supports names and values that are encodable by the current locale settings (see QTextCodec::codecForLocale).

On Windows, the variable names are case-insensitive. Therefore, QProcessEnvironment will always uppercase the names and do case-insensitive comparisons.

On Windows CE, the concept of environment does not exist. This class will keep the values set for compatibility with other platforms, but the values set will have no effect on the processes being created.

See also

QProcess, QProcess::systemEnvironment(), QProcess::setProcessEnvironment()

Definition at line 68 of file qprocess.h.

Constructors and Destructors

QProcessEnvironment() [1/2]

QProcessEnvironment::QProcessEnvironment

(

)

Creates a new QProcessEnvironment object.

This constructor creates an empty environment. If set on a QProcess, this will cause the current environment variables to be removed.

Definition at line 216 of file qprocess.cpp.

    : d(0)
{
}

QProcessEnvironment() [2/2]

QProcessEnvironment::QProcessEnvironment

(

const QProcessEnvironment &

other

)

Creates a QProcessEnvironment object that is a copy of other.

Definition at line 231 of file qprocess.cpp.

    : d(other.d)
{
}

~QProcessEnvironment()

QProcessEnvironment::~QProcessEnvironment

(

)

Frees the resources associated with this QProcessEnvironment object.

Definition at line 224 of file qprocess.cpp.

{
}

Functions

clear()

void QProcessEnvironment::clear

(

)

Removes all key=value pairs from this QProcessEnvironment object, making it empty.

See also

isEmpty(), systemEnvironment()

Definition at line 295 of file qprocess.cpp.

{
    if (d)
        d->hash.clear();
    // Unix: Don't clear d->nameMap, as the environment is likely to be
    // re-populated with the same keys again.
}

contains()

bool QProcessEnvironment::contains

(

const QString &

name

)

const

Returns true if the environment variable of name name is found in this QProcessEnvironment object.

On Windows, variable names are case-insensitive, so the key is converted to uppercase before searching. On other systems, names are case-sensitive so no trasformation is applied.

See also

insert(), value()

Definition at line 313 of file qprocess.cpp.

{
    if (!d)
        return false;
    QProcessEnvironmentPrivate::MutexLocker locker(d);
    return d->hash.contains(d->prepareName(name));
}

insert() [1/2]

void QProcessEnvironment::insert	(	const QString &	name,
		const QString &	value
	)

Inserts the environment variable of name name and contents value into this QProcessEnvironment object.

If that variable already existed, it is replaced by the new value.

On Windows, variable names are case-insensitive, so this function always uppercases the variable name before inserting. On other systems, names are case-sensitive, so no transformation is applied.

On most systems, inserting a variable with no contents will have the same effect for applications as if the variable had not been set at all. However, to guarantee that there are no incompatibilities, to remove a variable, please use the remove() function.

See also

contains(), remove(), value()

Definition at line 337 of file qprocess.cpp.

Referenced by QProcessEnvironmentPrivate::fromList().

{
    // our re-impl of detach() detaches from null
    d.detach(); // detach before prepareName()
    d->hash.insert(d->prepareName(name), d->prepareValue(value));
}

insert() [2/2]

void QProcessEnvironment::insert

(

const QProcessEnvironment &

e

)

Inserts the contents of e in this QProcessEnvironment object.

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since

4.8

Variables in this object that also exist in e will be overwritten.

Definition at line 435 of file qprocess.cpp.

{
    if (!e.d)
        return;

    // our re-impl of detach() detaches from null
    QProcessEnvironmentPrivate::MutexLocker locker(e.d);
    d->insert(*e.d);
}

isEmpty()

bool QProcessEnvironment::isEmpty

(

)

const

Returns true if this QProcessEnvironment object is empty: that is there are no key=value pairs set.

See also

clear(), systemEnvironment(), insert()

Definition at line 283 of file qprocess.cpp.

{
    // Needs no locking, as no hash nodes are accessed
    return d ? d->hash.isEmpty() : true;
}

keys()

QStringList QProcessEnvironment::keys

(

)

const

Returns a list containing all the variable names in this QProcessEnvironment object.

Since

4.8

Definition at line 417 of file qprocess.cpp.

{
    if (!d)
        return QStringList();
    QProcessEnvironmentPrivate::MutexLocker locker(d);
    return d->keys();
}

operator!=()

bool QProcessEnvironment::operator!= ( const QProcessEnvironment &  other ) const

inline

Returns true if this and the other QProcessEnvironment objects are different.

See also

operator==()

Definition at line 77 of file qprocess.h.

    { return !(*this == other); }

operator=()

QProcessEnvironment & QProcessEnvironment::operator=

(

const QProcessEnvironment &

other

)

Copies the contents of the other QProcessEnvironment object into this one.

Definition at line 240 of file qprocess.cpp.

{
    d = other.d;
    return *this;
}

operator==()

bool QProcessEnvironment::operator==

(

const QProcessEnvironment &

other

)

const

Returns true if this and the other QProcessEnvironment objects are equal.

Two QProcessEnvironment objects are considered equal if they have the same set of key=value pairs. The comparison of keys is done case-sensitive on platforms where the environment is case-sensitive.

See also

operator!=(), contains()

Definition at line 266 of file qprocess.cpp.

{
    if (d == other.d)
        return true;
    if (d && other.d) {
        QProcessEnvironmentPrivate::OrderedMutexLocker locker(d, other.d);
        return d->hash == other.d->hash;
    }
    return false;
}

remove()

void QProcessEnvironment::remove

(

const QString &

name

)

Removes the environment variable identified by name from this QProcessEnvironment object.

If that variable did not exist before, nothing happens.

On Windows, variable names are case-insensitive, so the key is converted to uppercase before searching. On other systems, names are case-sensitive so no trasformation is applied.

See also

contains(), insert(), value()

Definition at line 355 of file qprocess.cpp.

{
    if (d) {
        d.detach(); // detach before prepareName()
        d->hash.remove(d->prepareName(name));
    }
}

systemEnvironment()

QProcessEnvironment QProcessEnvironment::systemEnvironment ( )

static

The systemEnvironment function returns the environment of the calling process.

Since

4.6

It is returned as a QProcessEnvironment. This function does not cache the system environment. Therefore, it's possible to obtain an updated version of the environment if low-level C library functions like setenv ot putenv have been called.

However, note that repeated calls to this function will recreate the QProcessEnvironment object, which is a non-trivial operation.

See also

QProcess::systemEnvironment()

Definition at line 499 of file qprocess_unix.cpp.

Referenced by qt_create_commandline().

{
    QProcessEnvironment env;
#if !defined(Q_OS_IOS)
    const char *entry;
    for (int count = 0; (entry = environ[count]); ++count) {
        const char *equal = strchr(entry, '=');
        if (!equal)
            continue;

        QByteArray name(entry, equal - entry);
        QByteArray value(equal + 1);
        env.d->hash.insert(QProcessEnvironmentPrivate::Key(name),
                           QProcessEnvironmentPrivate::Value(value));
    }
#endif
    return env;
}

toStringList()

QStringList QProcessEnvironment::toStringList

(

)

const

Converts this QProcessEnvironment object into a list of strings, one for each environment variable that is set.

The environment variable's name and its value are separated by an equal character ('=').

The QStringList contents returned by this function are suitable for use with the QProcess::setEnvironment function. However, it is recommended to use QProcess::setProcessEnvironment instead since that will avoid unnecessary copying of the data.

See also

systemEnvironment(), QProcess::systemEnvironment(), QProcess::environment(), QProcess::setEnvironment()

Definition at line 400 of file qprocess.cpp.

{
    if (!d)
        return QStringList();
    QProcessEnvironmentPrivate::MutexLocker locker(d);
    return d->toList();
}

value()

QString QProcessEnvironment::value	(	const QString &	name,
		const QString &	defaultValue = QString()
	)		const

Searches this QProcessEnvironment object for a variable identified by name and returns its value.

If the variable is not found in this object, then defaultValue is returned instead.

On Windows, variable names are case-insensitive, so the key is converted to uppercase before searching. On other systems, names are case-sensitive so no trasformation is applied.

See also

contains(), insert(), remove()

Definition at line 374 of file qprocess.cpp.

{
    if (!d)
        return defaultValue;

    QProcessEnvironmentPrivate::MutexLocker locker(d);
    QProcessEnvironmentPrivate::Hash::ConstIterator it = d->hash.constFind(d->prepareName(name));
    if (it == d->hash.constEnd())
        return defaultValue;

    return d->valueToString(it.value());
}

Friends and Related Functions

QProcessEnvironmentPrivate

friend class QProcessEnvironmentPrivate

friend

Definition at line 98 of file qprocess.h.

QProcessPrivate

friend class QProcessPrivate

friend

Definition at line 97 of file qprocess.h.

Properties

d

QSharedDataPointer<QProcessEnvironmentPrivate> QProcessEnvironment::d

private

Definition at line 99 of file qprocess.h.

Referenced by clear(), contains(), insert(), isEmpty(), keys(), operator=(), operator==(), qt_create_commandline(), remove(), systemEnvironment(), toStringList(), and value().

---

The documentation for this class was generated from the following files:

• /src/corelib/io/qprocess.h
• /src/corelib/io/qprocess.cpp
• /src/corelib/io/qprocess_unix.cpp
• /src/corelib/io/qprocess_win.cpp