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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QProcess Class Reference</h1>
<p>The QProcess class is used to start external programs and
to communicate with them.
<a href="#details">More...</a>
<p><tt>#include &lt;<a href="qprocess-h.html">qprocess.h</a>&gt;</tt>
<p>Inherits <a href="qobject.html">QObject</a>.
<p><a href="qprocess-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li class=fn><a href="#QProcess"><b>QProcess</b></a> ( QObject&nbsp;*&nbsp;parent = 0, const&nbsp;char&nbsp;*&nbsp;name = 0 )</li>
<li class=fn><a href="#QProcess-2"><b>QProcess</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;arg0, QObject&nbsp;*&nbsp;parent = 0, const&nbsp;char&nbsp;*&nbsp;name = 0 )</li>
<li class=fn><a href="#QProcess-3"><b>QProcess</b></a> ( const&nbsp;QStringList&nbsp;&amp;&nbsp;args, QObject&nbsp;*&nbsp;parent = 0, const&nbsp;char&nbsp;*&nbsp;name = 0 )</li>
<li class=fn><a href="#~QProcess"><b>~QProcess</b></a> ()</li>
<li class=fn>QStringList <a href="#arguments"><b>arguments</b></a> () const</li>
<li class=fn>void <a href="#clearArguments"><b>clearArguments</b></a> ()</li>
<li class=fn>virtual void <a href="#setArguments"><b>setArguments</b></a> ( const&nbsp;QStringList&nbsp;&amp;&nbsp;args )</li>
<li class=fn>virtual void <a href="#addArgument"><b>addArgument</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;arg )</li>
<li class=fn>QDir <a href="#workingDirectory"><b>workingDirectory</b></a> () const</li>
<li class=fn>virtual void <a href="#setWorkingDirectory"><b>setWorkingDirectory</b></a> ( const&nbsp;QDir&nbsp;&amp;&nbsp;dir )</li>
<li class=fn>enum <a href="#Communication-enum"><b>Communication</b></a> { Stdin = 0x01, Stdout = 0x02, Stderr = 0x04, DupStderr = 0x08 }</li>
<li class=fn>void <a href="#setCommunication"><b>setCommunication</b></a> ( int&nbsp;commFlags )</li>
<li class=fn>int <a href="#communication"><b>communication</b></a> () const</li>
<li class=fn>virtual bool <a href="#start"><b>start</b></a> ( QStringList&nbsp;*&nbsp;env = 0 )</li>
<li class=fn>virtual bool <a href="#launch-2"><b>launch</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;buf, QStringList&nbsp;*&nbsp;env = 0 )</li>
<li class=fn>virtual bool <a href="#launch"><b>launch</b></a> ( const&nbsp;QByteArray&nbsp;&amp;&nbsp;buf, QStringList&nbsp;*&nbsp;env = 0 )</li>
<li class=fn>bool <a href="#isRunning"><b>isRunning</b></a> () const</li>
<li class=fn>bool <a href="#normalExit"><b>normalExit</b></a> () const</li>
<li class=fn>int <a href="#exitStatus"><b>exitStatus</b></a> () const</li>
<li class=fn>virtual QByteArray <a href="#readStdout"><b>readStdout</b></a> ()</li>
<li class=fn>virtual QByteArray <a href="#readStderr"><b>readStderr</b></a> ()</li>
<li class=fn>bool <a href="#canReadLineStdout"><b>canReadLineStdout</b></a> () const</li>
<li class=fn>bool <a href="#canReadLineStderr"><b>canReadLineStderr</b></a> () const</li>
<li class=fn>virtual QString <a href="#readLineStdout"><b>readLineStdout</b></a> ()</li>
<li class=fn>virtual QString <a href="#readLineStderr"><b>readLineStderr</b></a> ()</li>
<li class=fn>PID <a href="#processIdentifier"><b>processIdentifier</b></a> ()</li>
</ul>
<h2>Public Slots</h2>
<ul>
<li class=fn>void <a href="#tryTerminate"><b>tryTerminate</b></a> () const</li>
<li class=fn>void <a href="#kill"><b>kill</b></a> () const</li>
<li class=fn>virtual void <a href="#writeToStdin"><b>writeToStdin</b></a> ( const&nbsp;QByteArray&nbsp;&amp;&nbsp;buf )</li>
<li class=fn>virtual void <a href="#writeToStdin-2"><b>writeToStdin</b></a> ( const&nbsp;QString&nbsp;&amp;&nbsp;buf )</li>
<li class=fn>virtual void <a href="#closeStdin"><b>closeStdin</b></a> ()</li>
</ul>
<h2>Signals</h2>
<ul>
<li class=fn>void <a href="#readyReadStdout"><b>readyReadStdout</b></a> ()</li>
<li class=fn>void <a href="#readyReadStderr"><b>readyReadStderr</b></a> ()</li>
<li class=fn>void <a href="#processExited"><b>processExited</b></a> ()</li>
<li class=fn>void <a href="#wroteToStdin"><b>wroteToStdin</b></a> ()</li>
<li class=fn>void <a href="#launchFinished"><b>launchFinished</b></a> ()</li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
<p> The QProcess class is used to start external programs and
to communicate with them.
<p>
<p> You can write to the started program's standard input, and can
read the program's standard output and standard error. You can
pass command line arguments to the program either in the
constructor or with <a href="#setArguments">setArguments</a>() or <a href="#addArgument">addArgument</a>(). The program's
working directory can be set with <a href="#setWorkingDirectory">setWorkingDirectory</a>(). If you
need to set up environment variables pass them to the <a href="#start">start</a>() or
<a href="#launch">launch</a>() functions (see below). The <a href="#processExited">processExited</a>() signal is
emitted if the program exits. The program's exit status is
available from <a href="#exitStatus">exitStatus</a>(), although you could simply call
<a href="#normalExit">normalExit</a>() to see if the program terminated normally.
<p> There are two different ways to start a process. If you just want
to run a program, optionally passing data to its standard input at
the beginning, use one of the launch() functions. If you want full
control of the program's standard input (especially if you don't
know all the data you want to send to standard input at the
beginning), use the start() function.
<p> If you use start() you can write to the program's standard input
using <a href="#writeToStdin">writeToStdin</a>() and you can close the standard input with
<a href="#closeStdin">closeStdin</a>(). The <a href="#wroteToStdin">wroteToStdin</a>() signal is emitted if the data
sent to standard input has been written. You can read from the
program's standard output using <a href="#readStdout">readStdout</a>() or <a href="#readLineStdout">readLineStdout</a>().
These functions return an empty <a href="qbytearray.html">QByteArray</a> if there is no data to
read. The <a href="#readyReadStdout">readyReadStdout</a>() signal is emitted when there is data
available to be read from standard output. Standard error has a
set of functions that correspond to the standard output functions,
i.e. <a href="#readStderr">readStderr</a>(), <a href="#readLineStderr">readLineStderr</a>() and <a href="#readyReadStderr">readyReadStderr</a>().
<p> If you use one of the <a href="#launch">launch</a>() functions the data you pass will be
sent to the program's standard input which will be closed once all
the data has been written. You should <em>not</em> use <a href="#writeToStdin">writeToStdin</a>() or
<a href="#closeStdin">closeStdin</a>() if you use launch(). If you need to send data to the
program's standard input after it has started running use <a href="#start">start</a>()
instead of launch().
<p> Both start() and launch() can accept a string list of strings each
of which has the format, key=value, where the keys are the names
of environment variables.
<p> You can test to see if a program is running with <a href="#isRunning">isRunning</a>(). The
program's process identifier is available from
<a href="#processIdentifier">processIdentifier</a>(). If you want to terminate a running program
use <a href="#tryTerminate">tryTerminate</a>(), but note that the program may ignore this. If
you <em>really</em> want to terminate the program, without it having any
chance to clean up, you can use <a href="#kill">kill</a>().
<p> As an example, suppose we want to start the <tt>uic</tt> command (a Qt
command line tool used with <em>Qt Designer</em>) and perform some
operations on the output (the <tt>uic</tt> outputs the code it generates
to standard output by default). Suppose further that we want to
run the program on the file "small_dialog.ui" with the command
line options "-tr <a href="i18n.html#i18n">i18n</a>". On the command line we would write:
<pre>
uic -tr i18n small_dialog.ui
</pre>
<p>
<p> A code snippet for this with the QProcess class might look like
this:
<p> <pre> UicManager::UicManager()
{
</pre><pre> proc = new QProcess( this );
</pre><pre> <a name="x2122"></a> proc-&gt;<a href="#addArgument">addArgument</a>( "uic" );
proc-&gt;<a href="#addArgument">addArgument</a>( "-tr" );
proc-&gt;<a href="#addArgument">addArgument</a>( "i18n" );
proc-&gt;<a href="#addArgument">addArgument</a>( "small_dialog.ui" );
<a name="x2123"></a> <a href="qobject.html#connect">connect</a>( proc, SIGNAL(<a href="#readyReadStdout">readyReadStdout</a>()),
this, SLOT(readFromStdout()) );
</pre><pre> <a name="x2124"></a> if ( !proc-&gt;<a href="#start">start</a>() ) {
// error handling
</pre><pre> }
}
</pre>
<p> <pre> void UicManager::readFromStdout()
{
// Read and process the data.
// Bear in mind that the data might be output in chunks.
</pre><pre> }
</pre>
<p> Although you may need quotes for a file named on the command line
(e.g. if it contains spaces) you shouldn't use extra quotes for
arguments passed to <a href="#addArgument">addArgument</a>() or <a href="#setArguments">setArguments</a>().
<p> The <a href="#readyReadStdout">readyReadStdout</a>() signal is emitted when there is new data on
standard output. This happens asynchronously: you don't know if
more data will arrive later.
<p> In the above example you could connect the <a href="#processExited">processExited</a>() signal
to the slot UicManager::readFromStdout() instead. If you do so,
you will be certain that all the data is available when the slot
is called. On the other hand, you must wait until the process has
finished before doing any processing.
<p> Note that if you are expecting a lot of output from the process,
you may hit platform-dependent limits to the pipe buffer size. The
solution is to make sure you connect to the output, e.g. the
readyReadStdout() and <a href="#readyReadStderr">readyReadStderr</a>() signals and read the data
as soon as it becomes available.
<p> Please note that QProcess does not emulate a shell. This means that
QProcess does not do any expansion of arguments: a '*' is passed as a '*'
to the program and is <em>not</em> replaced by all the files, a '$HOME' is also
passed literally and is <em>not</em> replaced by the environment variable HOME
and the special characters for IO redirection ('>', '|', etc.) are also
passed literally and do <em>not</em> have the special meaning as they have in a
shell.
<p> Also note that QProcess does not emulate a terminal. This means that
certain programs which need direct terminal control, do not work as
expected with QProcess. Such programs include console email programs (like
pine and mutt) but also programs which require the user to enter a password
(like su and ssh).
<p> <h3> Notes for Windows users
</h3>
<a name="1"></a><p> Some Windows commands, for example, <tt>dir</tt>, are not provided by
separate applications, but by the command interpreter.
If you attempt to use QProcess to execute these commands directly
it won't work. One possible solution is to execute the command
interpreter itself (<tt>cmd.exe</tt> on some Windows systems), and ask
the interpreter to execute the desired command.
<p> Under Windows there are certain problems starting 16-bit applications
and capturing their output. Microsoft recommends using an intermediate
application to start 16-bit applications.
<p> <p>See also <a href="qsocket.html">QSocket</a>, <a href="io.html">Input/Output and Networking</a>, and <a href="misc.html">Miscellaneous Classes</a>.
<hr><h2>Member Type Documentation</h2>
<h3 class=fn><a name="Communication-enum"></a>QProcess::Communication</h3>
<p> This enum type defines the communication channels connected to the
process.
<ul>
<li><tt>QProcess::Stdin</tt> - Data can be written to the process's standard input.
<li><tt>QProcess::Stdout</tt> - Data can be read from the process's standard
output.
<li><tt>QProcess::Stderr</tt> - Data can be read from the process's standard error.
<li><tt>QProcess::DupStderr</tt> - Both the process's standard error output <em>and</em>
its standard output are written to its standard output. (Like
Unix's dup2().) This means that nothing is sent to the standard
error output. This is especially useful if your application
requires that the output on standard output and on standard error
must be read in the same order that they are produced. This is a
flag, so to activate it you must pass <tt>Stdout|Stderr|DupStderr</tt>,
or <tt>Stdin|Stdout|Stderr|DupStderr</tt> if you want to provide input,
to the <a href="#setCommunication">setCommunication</a>() call.
</ul><p> <p>See also <a href="#setCommunication">setCommunication</a>() and <a href="#communication">communication</a>().
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="QProcess"></a>QProcess::QProcess ( <a href="qobject.html">QObject</a>&nbsp;*&nbsp;parent = 0, const&nbsp;char&nbsp;*&nbsp;name = 0 )
</h3>
Constructs a QProcess object. The <em>parent</em> and <em>name</em> parameters
are passed to the <a href="qobject.html">QObject</a> constructor.
<p> <p>See also <a href="#setArguments">setArguments</a>(), <a href="#addArgument">addArgument</a>(), and <a href="#start">start</a>().
<h3 class=fn><a name="QProcess-2"></a>QProcess::QProcess ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;arg0, <a href="qobject.html">QObject</a>&nbsp;*&nbsp;parent = 0, const&nbsp;char&nbsp;*&nbsp;name = 0 )
</h3>
Constructs a QProcess with <em>arg0</em> as the command to be executed.
The <em>parent</em> and <em>name</em> parameters are passed to the <a href="qobject.html">QObject</a>
constructor.
<p> The process is not started. You must call <a href="#start">start</a>() or <a href="#launch">launch</a>() to
start the process.
<p> <p>See also <a href="#setArguments">setArguments</a>(), <a href="#addArgument">addArgument</a>(), and <a href="#start">start</a>().
<h3 class=fn><a name="QProcess-3"></a>QProcess::QProcess ( const&nbsp;<a href="qstringlist.html">QStringList</a>&nbsp;&amp;&nbsp;args, <a href="qobject.html">QObject</a>&nbsp;*&nbsp;parent = 0, const&nbsp;char&nbsp;*&nbsp;name = 0 )
</h3>
Constructs a QProcess with <em>args</em> as the arguments of the
process. The first element in the list is the command to be
executed. The other elements in the list are the arguments to this
command. The <em>parent</em> and <em>name</em> parameters are passed to the
<a href="qobject.html">QObject</a> constructor.
<p> The process is not started. You must call <a href="#start">start</a>() or <a href="#launch">launch</a>() to
start the process.
<p> <p>See also <a href="#setArguments">setArguments</a>(), <a href="#addArgument">addArgument</a>(), and <a href="#start">start</a>().
<h3 class=fn><a name="~QProcess"></a>QProcess::~QProcess ()
</h3>
Destroys the instance.
<p> If the process is running, it is <b>not</b> terminated! The
standard input, standard output and standard error of the process
are closed.
<p> You can connect the <a href="qobject.html#destroyed">destroyed</a>() signal to the <a href="#kill">kill</a>() slot, if you
want the process to be terminated automatically when the instance
is destroyed.
<p> <p>See also <a href="#tryTerminate">tryTerminate</a>() and <a href="#kill">kill</a>().
<h3 class=fn>void <a name="addArgument"></a>QProcess::addArgument ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;arg )<tt> [virtual]</tt>
</h3>
Adds <em>arg</em> to the end of the list of arguments.
<p> The first element in the list of arguments is the command to be
executed; the following elements are the command's arguments.
<p> <p>See also <a href="#arguments">arguments</a>() and <a href="#setArguments">setArguments</a>().
<p>Example: <a href="qprocess.html#x2122">process/process.cpp</a>.
<h3 class=fn><a href="qstringlist.html">QStringList</a> <a name="arguments"></a>QProcess::arguments () const
</h3>
Returns the list of arguments that are set for the process.
Arguments can be specified with the constructor or with the
functions <a href="#setArguments">setArguments</a>() and <a href="#addArgument">addArgument</a>().
<p> Note that if you want to iterate over the list, you should iterate
over a copy, e.g.
<pre>
<a href="qstringlist.html">QStringList</a> list = myProcess.arguments();
QStringList::Iterator it = list.<a href="qvaluelist.html#begin">begin</a>();
while( it != list.<a href="qvaluelist.html#end">end</a>() ) {
myProcessing( *it );
++it;
}
</pre>
<p> <p>See also <a href="#setArguments">setArguments</a>() and <a href="#addArgument">addArgument</a>().
<h3 class=fn>bool <a name="canReadLineStderr"></a>QProcess::canReadLineStderr () const
</h3>
Returns TRUE if it's possible to read an entire line of text from
standard error at this time; otherwise returns FALSE.
<p> <p>See also <a href="#readLineStderr">readLineStderr</a>() and <a href="#canReadLineStdout">canReadLineStdout</a>().
<h3 class=fn>bool <a name="canReadLineStdout"></a>QProcess::canReadLineStdout () const
</h3>
Returns TRUE if it's possible to read an entire line of text from
standard output at this time; otherwise returns FALSE.
<p> <p>See also <a href="#readLineStdout">readLineStdout</a>() and <a href="#canReadLineStderr">canReadLineStderr</a>().
<h3 class=fn>void <a name="clearArguments"></a>QProcess::clearArguments ()
</h3>
Clears the list of arguments that are set for the process.
<p> <p>See also <a href="#setArguments">setArguments</a>() and <a href="#addArgument">addArgument</a>().
<h3 class=fn>void <a name="closeStdin"></a>QProcess::closeStdin ()<tt> [virtual slot]</tt>
</h3>
Closes the process's standard input.
<p> This function also deletes any pending data that has not been
written to standard input.
<p> <p>See also <a href="#wroteToStdin">wroteToStdin</a>().
<h3 class=fn>int <a name="communication"></a>QProcess::communication () const
</h3>
Returns the communication required with the process, i.e. some
combination of the <a href="#Communication-enum">Communication</a> flags.
<p> <p>See also <a href="#setCommunication">setCommunication</a>().
<h3 class=fn>int <a name="exitStatus"></a>QProcess::exitStatus () const
</h3>
Returns the exit status of the process or 0 if the process is
still running. This function returns immediately and does not wait
until the process is finished.
<p> If <a href="#normalExit">normalExit</a>() is FALSE (e.g. if the program was killed or
crashed), this function returns 0, so you should check the return
value of normalExit() before relying on this value.
<p> <p>See also <a href="#normalExit">normalExit</a>() and <a href="#processExited">processExited</a>().
<h3 class=fn>bool <a name="isRunning"></a>QProcess::isRunning () const
</h3>
Returns TRUE if the process is running; otherwise returns FALSE.
<p> <p>See also <a href="#normalExit">normalExit</a>(), <a href="#exitStatus">exitStatus</a>(), and <a href="#processExited">processExited</a>().
<h3 class=fn>void <a name="kill"></a>QProcess::kill () const<tt> [slot]</tt>
</h3>
Terminates the process. This is not a safe way to end a process
since the process will not be able to do any cleanup.
<a href="#tryTerminate">tryTerminate</a>() is safer, but processes can ignore a
tryTerminate().
<p> The nice way to end a process and to be sure that it is finished,
is to do something like this:
<pre>
process-&gt;tryTerminate();
QTimer::<a href="qtimer.html#singleShot">singleShot</a>( 5000, process, SLOT( <a href="#kill">kill</a>() ) );
</pre>
<p> This tries to terminate the process the nice way. If the process
is still running after 5 seconds, it terminates the process the
hard way. The timeout should be chosen depending on the time the
process needs to do all its cleanup: use a higher value if the
process is likely to do a lot of computation or I/O on cleanup.
<p> The slot returns immediately: it does not wait until the process
has finished. When the process terminates, the <a href="#processExited">processExited</a>()
signal is emitted.
<p> <p>See also <a href="#tryTerminate">tryTerminate</a>() and <a href="#processExited">processExited</a>().
<h3 class=fn>bool <a name="launch"></a>QProcess::launch ( const&nbsp;<a href="qbytearray.html">QByteArray</a>&nbsp;&amp;&nbsp;buf, <a href="qstringlist.html">QStringList</a>&nbsp;*&nbsp;env = 0 )<tt> [virtual]</tt>
</h3>
Runs the process and writes the data <em>buf</em> to the process's
standard input. If all the data is written to standard input,
standard input is closed. The command is searched for in the path
for executable programs; you can also use an absolute path in the
command itself.
<p> If <em>env</em> is null, then the process is started with the same
environment as the starting process. If <em>env</em> is non-null, then
the values in the string list are interpreted as environment
setttings of the form <tt>key=value</tt> and the process is started
with these environment settings. For convenience, there is a small
exception to this rule under Unix: if <em>env</em> does not contain any
settings for the environment variable <tt>LD_LIBRARY_PATH</tt>, then
this variable is inherited from the starting process.
<p> Returns TRUE if the process could be started; otherwise returns
FALSE.
<p> Note that you should not use the slots <a href="#writeToStdin">writeToStdin</a>() and
<a href="#closeStdin">closeStdin</a>() on processes started with <a href="#launch">launch</a>(), since the result
is not well-defined. If you need these slots, use <a href="#start">start</a>() instead.
<p> The process may or may not read the <em>buf</em> data sent to its
standard input.
<p> You can call this function even when a process that was started
with this instance is still running. Be aware that if you do this
the standard input of the process that was launched first will be
closed, with any pending data being deleted, and the process will
be left to run out of your control. Similarly, if the process
could not be started the standard input will be closed and the
pending data deleted. (On operating systems that have zombie
processes, Qt will also wait() on the old process.)
<p> The object emits the signal <a href="#launchFinished">launchFinished</a>() when this function
call is finished. If the start was successful, this signal is
emitted after all the data has been written to standard input. If
the start failed, then this signal is emitted immediately.
<p> <p>See also <a href="#start">start</a>() and <a href="#launchFinished">launchFinished</a>().
<h3 class=fn>bool <a name="launch-2"></a>QProcess::launch ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;buf, <a href="qstringlist.html">QStringList</a>&nbsp;*&nbsp;env = 0 )<tt> [virtual]</tt>
</h3>
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
<p> The data <em>buf</em> is written to standard input with <a href="#writeToStdin">writeToStdin</a>()
using the <a href="qstring.html#local8Bit">QString::local8Bit</a>() representation of the strings.
<h3 class=fn>void <a name="launchFinished"></a>QProcess::launchFinished ()<tt> [signal]</tt>
</h3>
<p> This signal is emitted when the process was started with <a href="#launch">launch</a>().
If the start was successful, this signal is emitted after all the
data has been written to standard input. If the start failed, then
this signal is emitted immediately.
<p> This signal is especially useful if you want to know when you can
safely delete the QProcess object when you are not interested in
reading from standard output or standard error.
<p> <p>See also <a href="#launch">launch</a>() and <a href="qobject.html#deleteLater">QObject::deleteLater</a>().
<h3 class=fn>bool <a name="normalExit"></a>QProcess::normalExit () const
</h3>
Returns TRUE if the process has exited normally; otherwise returns
FALSE. This implies that this function returns FALSE if the
process is still running.
<p> <p>See also <a href="#isRunning">isRunning</a>(), <a href="#exitStatus">exitStatus</a>(), and <a href="#processExited">processExited</a>().
<h3 class=fn>void <a name="processExited"></a>QProcess::processExited ()<tt> [signal]</tt>
</h3>
<p> This signal is emitted when the process has exited.
<p> <p>See also <a href="#isRunning">isRunning</a>(), <a href="#normalExit">normalExit</a>(), <a href="#exitStatus">exitStatus</a>(), <a href="#start">start</a>(), and <a href="#launch">launch</a>().
<p>Example: <a href="process-example.html#x98">process/process.cpp</a>.
<h3 class=fn>PID <a name="processIdentifier"></a>QProcess::processIdentifier ()
</h3>
Returns platform dependent information about the process. This can
be used together with platform specific system calls.
<p> Under Unix the return value is the PID of the process, or -1 if no
process belongs to this object.
<p> Under Windows it is a pointer to the <tt>PROCESS_INFORMATION</tt>
struct, or 0 if no process is belongs to this object.
<p> Use of this function's return value is likely to be non-portable.
<h3 class=fn><a href="qstring.html">QString</a> <a name="readLineStderr"></a>QProcess::readLineStderr ()<tt> [virtual]</tt>
</h3>
Reads a line of text from standard error, excluding any trailing
newline or carriage return characters and returns it. Returns
<a href="qstring.html#QString-null">QString::null</a> if <a href="#canReadLineStderr">canReadLineStderr</a>() returns FALSE.
<p> By default, the text is interpreted to be in Latin-1 encoding. If you need
other codecs, you can set a different codec with
<a href="qtextcodec.html#setCodecForCStrings">QTextCodec::setCodecForCStrings</a>().
<p> <p>See also <a href="#canReadLineStderr">canReadLineStderr</a>(), <a href="#readyReadStderr">readyReadStderr</a>(), <a href="#readStderr">readStderr</a>(), and <a href="#readLineStdout">readLineStdout</a>().
<h3 class=fn><a href="qstring.html">QString</a> <a name="readLineStdout"></a>QProcess::readLineStdout ()<tt> [virtual]</tt>
</h3>
Reads a line of text from standard output, excluding any trailing
newline or carriage return characters, and returns it. Returns
<a href="qstring.html#QString-null">QString::null</a> if <a href="#canReadLineStdout">canReadLineStdout</a>() returns FALSE.
<p> By default, the text is interpreted to be in Latin-1 encoding. If you need
other codecs, you can set a different codec with
<a href="qtextcodec.html#setCodecForCStrings">QTextCodec::setCodecForCStrings</a>().
<p> <p>See also <a href="#canReadLineStdout">canReadLineStdout</a>(), <a href="#readyReadStdout">readyReadStdout</a>(), <a href="#readStdout">readStdout</a>(), and <a href="#readLineStderr">readLineStderr</a>().
<h3 class=fn><a href="qbytearray.html">QByteArray</a> <a name="readStderr"></a>QProcess::readStderr ()<tt> [virtual]</tt>
</h3>
Reads the data that the process has written to standard error.
When new data is written to standard error, the class emits the
signal <a href="#readyReadStderr">readyReadStderr</a>().
<p> If there is no data to read, this function returns a <a href="qbytearray.html">QByteArray</a> of
size 0: it does not wait until there is something to read.
<p> <p>See also <a href="#readyReadStderr">readyReadStderr</a>(), <a href="#readLineStderr">readLineStderr</a>(), <a href="#readStdout">readStdout</a>(), and <a href="#writeToStdin">writeToStdin</a>().
<h3 class=fn><a href="qbytearray.html">QByteArray</a> <a name="readStdout"></a>QProcess::readStdout ()<tt> [virtual]</tt>
</h3>
Reads the data that the process has written to standard output.
When new data is written to standard output, the class emits the
signal <a href="#readyReadStdout">readyReadStdout</a>().
<p> If there is no data to read, this function returns a <a href="qbytearray.html">QByteArray</a> of
size 0: it does not wait until there is something to read.
<p> <p>See also <a href="#readyReadStdout">readyReadStdout</a>(), <a href="#readLineStdout">readLineStdout</a>(), <a href="#readStderr">readStderr</a>(), and <a href="#writeToStdin">writeToStdin</a>().
<p>Example: <a href="process-example.html#x99">process/process.cpp</a>.
<h3 class=fn>void <a name="readyReadStderr"></a>QProcess::readyReadStderr ()<tt> [signal]</tt>
</h3>
<p> This signal is emitted when the process has written data to
standard error. You can read the data with <a href="#readStderr">readStderr</a>().
<p> Note that this signal is only emitted when there is new data and
not when there is old, but unread data. In the slot connected to
this signal, you should always read everything that is available
at that moment to make sure that you don't lose any data.
<p> <p>See also <a href="#readStderr">readStderr</a>(), <a href="#readLineStderr">readLineStderr</a>(), and <a href="#readyReadStdout">readyReadStdout</a>().
<h3 class=fn>void <a name="readyReadStdout"></a>QProcess::readyReadStdout ()<tt> [signal]</tt>
</h3>
<p> This signal is emitted when the process has written data to
standard output. You can read the data with <a href="#readStdout">readStdout</a>().
<p> Note that this signal is only emitted when there is new data and
not when there is old, but unread data. In the slot connected to
this signal, you should always read everything that is available
at that moment to make sure that you don't lose any data.
<p> <p>See also <a href="#readStdout">readStdout</a>(), <a href="#readLineStdout">readLineStdout</a>(), and <a href="#readyReadStderr">readyReadStderr</a>().
<p>Example: <a href="qprocess.html#x2123">process/process.cpp</a>.
<h3 class=fn>void <a name="setArguments"></a>QProcess::setArguments ( const&nbsp;<a href="qstringlist.html">QStringList</a>&nbsp;&amp;&nbsp;args )<tt> [virtual]</tt>
</h3>
Sets <em>args</em> as the arguments for the process. The first element
in the list is the command to be executed. The other elements in
the list are the arguments to the command. Any previous arguments
are deleted.
<p> QProcess does not perform argument substitutions; for example, if you
specify "*" or "$DISPLAY", these values are passed to the process
literally. If you want to have the same behavior as the shell
provides, you must do the substitutions yourself; i.e. instead of
specifying a "*" you must specify the list of all the filenames in
the current directory, and instead of "$DISPLAY" you must specify
the value of the environment variable <tt>DISPLAY</tt>.
<p> Note for Windows users. The standard Windows shells, e.g. <tt>command.com</tt> and <tt>cmd.exe</tt>, do not perform file globbing, i.e.
they do not convert a "*" on the command line into a list of files
in the current directory. For this reason most Windows
applications implement their own file globbing, and as a result of
this, specifying an argument of "*" for a Windows application is
likely to result in the application performing a file glob and
ending up with a list of filenames.
<p> <p>See also <a href="#arguments">arguments</a>() and <a href="#addArgument">addArgument</a>().
<h3 class=fn>void <a name="setCommunication"></a>QProcess::setCommunication ( int&nbsp;commFlags )
</h3>
Sets <em>commFlags</em> as the communication required with the process.
<p> <em>commFlags</em> is a bitwise OR of the flags defined by the <a href="#Communication-enum">Communication</a> enum.
<p> The default is <tt>Stdin|Stdout|Stderr</tt>.
<p> <p>See also <a href="#communication">communication</a>().
<h3 class=fn>void <a name="setWorkingDirectory"></a>QProcess::setWorkingDirectory ( const&nbsp;<a href="qdir.html">QDir</a>&nbsp;&amp;&nbsp;dir )<tt> [virtual]</tt>
</h3>
Sets <em>dir</em> as the working directory for processes. This does not
affect running processes; only processes that are started
afterwards are affected.
<p> Setting the working directory is especially useful for processes
that try to access files with relative paths.
<p> <p>See also <a href="#workingDirectory">workingDirectory</a>() and <a href="#start">start</a>().
<h3 class=fn>bool <a name="start"></a>QProcess::start ( <a href="qstringlist.html">QStringList</a>&nbsp;*&nbsp;env = 0 )<tt> [virtual]</tt>
</h3>
Tries to run a process for the command and arguments that were
specified with <a href="#setArguments">setArguments</a>(), <a href="#addArgument">addArgument</a>() or that were
specified in the constructor. The command is searched for in the
path for executable programs; you can also use an absolute path in
the command itself.
<p> If <em>env</em> is null, then the process is started with the same
environment as the starting process. If <em>env</em> is non-null, then
the values in the stringlist are interpreted as environment
setttings of the form <tt>key=value</tt> and the process is started in
these environment settings. For convenience, there is a small
exception to this rule: under Unix, if <em>env</em> does not contain any
settings for the environment variable <tt>LD_LIBRARY_PATH</tt>, then
this variable is inherited from the starting process; under
Windows the same applies for the environment variable <tt>PATH</tt>.
<p> Returns TRUE if the process could be started; otherwise returns
FALSE.
<p> You can write data to the process's standard input with
<a href="#writeToStdin">writeToStdin</a>(). You can close standard input with <a href="#closeStdin">closeStdin</a>() and
you can terminate the process with <a href="#tryTerminate">tryTerminate</a>(), or with <a href="#kill">kill</a>().
<p> You can call this function even if you've used this instance to
create a another process which is still running. In such cases,
QProcess closes the old process's standard input and deletes
pending data, i.e., you lose all control over the old process, but
the old process is not terminated. This applies also if the
process could not be started. (On operating systems that have
zombie processes, Qt will also wait() on the old process.)
<p> <p>See also <a href="#launch">launch</a>() and <a href="#closeStdin">closeStdin</a>().
<p>Example: <a href="qprocess.html#x2124">process/process.cpp</a>.
<h3 class=fn>void <a name="tryTerminate"></a>QProcess::tryTerminate () const<tt> [slot]</tt>
</h3>
Asks the process to terminate. Processes can ignore this if they
wish. If you want to be certain that the process really
terminates, you can use <a href="#kill">kill</a>() instead.
<p> The slot returns immediately: it does not wait until the process
has finished. When the process terminates, the <a href="#processExited">processExited</a>()
signal is emitted.
<p> <p>See also <a href="#kill">kill</a>() and <a href="#processExited">processExited</a>().
<h3 class=fn><a href="qdir.html">QDir</a> <a name="workingDirectory"></a>QProcess::workingDirectory () const
</h3>
Returns the working directory that was set with
<a href="#setWorkingDirectory">setWorkingDirectory</a>(), or the current directory if none has been
explicitly set.
<p> <p>See also <a href="#setWorkingDirectory">setWorkingDirectory</a>() and <a href="qdir.html#current">QDir::current</a>().
<h3 class=fn>void <a name="writeToStdin"></a>QProcess::writeToStdin ( const&nbsp;<a href="qbytearray.html">QByteArray</a>&nbsp;&amp;&nbsp;buf )<tt> [virtual slot]</tt>
</h3>
Writes the data <em>buf</em> to the process's standard input. The
process may or may not read this data.
<p> This function always returns immediately. The data you
pass to <a href="#writeToStdin">writeToStdin</a>() is copied into an internal memory buffer in
QProcess, and when control goes back to the event loop, QProcess will
starting transferring data from this buffer to the running process. <20>
Sometimes the data will be transferred in several payloads, depending on
how much data is read at a time by the process itself. When QProcess has
transferred all the data from its memory buffer to the running process, it
emits <a href="#wroteToStdin">wroteToStdin</a>().
<p> Note that some operating systems use a buffer to transfer
the data. As a result, wroteToStdin() may be emitted before the
running process has actually read all the data.
<p> <p>See also <a href="#wroteToStdin">wroteToStdin</a>(), <a href="#closeStdin">closeStdin</a>(), <a href="#readStdout">readStdout</a>(), and <a href="#readStderr">readStderr</a>().
<h3 class=fn>void <a name="writeToStdin-2"></a>QProcess::writeToStdin ( const&nbsp;<a href="qstring.html">QString</a>&nbsp;&amp;&nbsp;buf )<tt> [virtual slot]</tt>
</h3>
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
<p> The string <em>buf</em> is handled as text using the
<a href="qstring.html#local8Bit">QString::local8Bit</a>() representation.
<h3 class=fn>void <a name="wroteToStdin"></a>QProcess::wroteToStdin ()<tt> [signal]</tt>
</h3>
<p> This signal is emitted if the data sent to standard input (via
<a href="#writeToStdin">writeToStdin</a>()) was actually written to the process. This does not
imply that the process really read the data, since this class only
detects when it was able to write the data to the operating
system. But it is now safe to close standard input without losing
pending data.
<p> <p>See also <a href="#writeToStdin">writeToStdin</a>() and <a href="#closeStdin">closeStdin</a>().
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<td>Copyright &copy; 2007
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
<td align=right><div align=right>Qt 3.3.8</div>
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