summaryrefslogtreecommitdiffstats
path: root/src/qt3support/other/q3process.cpp
blob: f5716f53f8be3fd04e788b1181532b568771035a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the Qt3Support module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights.  These rights are described in the Nokia Qt LGPL
** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "q3process.h"

#ifndef QT_NO_PROCESS

#include "qapplication.h"
#include "private/q3membuf_p.h"

#include <stdio.h>
#include <stdlib.h>

QT_BEGIN_NAMESPACE

//#define QT_Q3PROCESS_DEBUG


/*!
    \class Q3Process

    \brief The Q3Process class is used to start external programs and
    to communicate with them.

    \compat

    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 setArguments() or addArgument(). The program's
    working directory can be set with setWorkingDirectory(). If you
    need to set up environment variables pass them to the start() or
    launch() functions (see below). The processExited() signal is
    emitted if the program exits. The program's exit status is
    available from exitStatus(), although you could simply call
    normalExit() to see if the program terminated normally.

    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.

    If you use start() you can write to the program's standard input
    using writeToStdin() and you can close the standard input with
    closeStdin(). The wroteToStdin() signal is emitted if the data
    sent to standard input has been written. You can read from the
    program's standard output using readStdout() or readLineStdout().
    These functions return an empty QByteArray if there is no data to
    read. The readyReadStdout() 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. readStderr(), readLineStderr() and readyReadStderr().

    If you use one of the launch() 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 \e not use writeToStdin() or
    closeStdin() if you use launch(). If you need to send data to the
    program's standard input after it has started running use start()
    instead of launch().

    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.

    You can test to see if a program is running with isRunning(). The
    program's process identifier is available from
    processIdentifier(). If you want to terminate a running program
    use tryTerminate(), but note that the program may ignore this. If
    you \e really want to terminate the program, without it having any
    chance to clean up, you can use kill().

    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 addArgument() or setArguments().

    The readyReadStdout() signal is emitted when there is new data on
    standard output. This happens asynchronously: you don't know if
    more data will arrive later.

    In the above example you could connect the processExited() 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.

    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 readyReadStderr() signals and read the data
    as soon as it becomes available.

    Please note that Q3Process does not emulate a shell. This means that
    Q3Process does not do any expansion of arguments: a '*' is passed as a '*'
    to the program and is \e not replaced by all the files, a '$HOME' is also
    passed literally and is \e not replaced by the environment variable HOME
    and the special characters for IO redirection ('>', '|', etc.) are also
    passed literally and do \e not have the special meaning as they have in a
    shell.

    Also note that Q3Process does not emulate a terminal. This means that
    certain programs which need direct terminal control, do not work as
    expected with Q3Process. 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).

    \section1 Notes for Windows users

    Some Windows commands, for example, \c dir, are not provided by
    separate applications, but by the command interpreter.
    If you attempt to use Q3Process to execute these commands directly
    it won't work. One possible solution is to execute the command
    interpreter itself (\c cmd.exe on some Windows systems), and ask
    the interpreter to execute the desired command.

    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.

    \sa Q3Socket
*/

/*!
    \enum Q3Process::Communication

    This enum type defines the communication channels connected to the
    process.

    \value Stdin  Data can be written to the process's standard input.

    \value Stdout  Data can be read from the process's standard
    output.

    \value Stderr  Data can be read from the process's standard error.

    \value DupStderr  Both the process's standard error output \e and
    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 \c{Stdout|Stderr|DupStderr},
    or \c{Stdin|Stdout|Stderr|DupStderr} if you want to provide input,
    to the setCommunication() call.

    \sa setCommunication() communication()
*/

/*!
    Constructs a Q3Process object. The \a parent and \a name parameters
    are passed to the QObject constructor.

    \sa setArguments() addArgument() start()
*/
Q3Process::Q3Process( QObject *parent, const char *name )
    : QObject( parent, name ), ioRedirection( false ), notifyOnExit( false ),
    wroteToStdinConnected( false ),
    readStdoutCalled( false ), readStderrCalled( false ),
    comms( Stdin|Stdout|Stderr )
{
    init();
}

/*!
    Constructs a Q3Process with \a arg0 as the command to be executed.
    The \a parent and \a name parameters are passed to the QObject
    constructor.

    The process is not started. You must call start() or launch() to
    start the process.

    \sa setArguments() addArgument() start()
*/
Q3Process::Q3Process( const QString& arg0, QObject *parent, const char *name )
    : QObject( parent, name ), ioRedirection( false ), notifyOnExit( false ),
    wroteToStdinConnected( false ),
    readStdoutCalled( false ), readStderrCalled( false ),
    comms( Stdin|Stdout|Stderr )
{
    init();
    addArgument( arg0 );
}

/*!
    Constructs a Q3Process with \a args 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 \a parent and \a name parameters are passed to the
    QObject constructor.

    The process is not started. You must call start() or launch() to
    start the process.

    \sa setArguments() addArgument() start()
*/
Q3Process::Q3Process( const QStringList& args, QObject *parent, const char *name )
    : QObject( parent, name ), ioRedirection( false ), notifyOnExit( false ),
    wroteToStdinConnected( false ),
    readStdoutCalled( false ), readStderrCalled( false ),
    comms( Stdin|Stdout|Stderr )
{
    init();
    setArguments( args );
}

/*!
    \fn Q3Process::~Q3Process()

    Destroys the instance.

    If the process is running, it is <b>not</b> terminated! The
    standard input, standard output and standard error of the process
    are closed.

    You can connect the destroyed() signal to the kill() slot, if you
    want the process to be terminated automatically when the instance
    is destroyed.

    \sa tryTerminate() kill()
*/

/*!
    Returns the list of arguments that are set for the process.
    Arguments can be specified with the constructor or with the
    functions setArguments() and addArgument().

    Note that if you want to iterate over the list, you should iterate
    over a copy, e.g.
    \snippet doc/src/snippets/code/src_qt3support_other_q3process.cpp 0

    \sa setArguments() addArgument()
*/
QStringList Q3Process::arguments() const
{
    return _arguments;
}

/*!
    Clears the list of arguments that are set for the process.

    \sa setArguments() addArgument()
*/
void Q3Process::clearArguments()
{
    _arguments.clear();
}

/*!
    Sets \a args 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.

    Q3Process 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 \c DISPLAY.

    Note for Windows users. The standard Windows shells, e.g. \c
    command.com and \c cmd.exe, 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.

    \sa arguments() addArgument()
*/
void Q3Process::setArguments( const QStringList& args )
{
    _arguments = args;
}

/*!
    Adds \a arg to the end of the list of arguments.

    The first element in the list of arguments is the command to be
    executed; the following elements are the command's arguments.

    \sa arguments() setArguments()
*/
void Q3Process::addArgument( const QString& arg )
{
    _arguments.append( arg );
}

#ifndef QT_NO_DIR
/*!
    Returns the working directory that was set with
    setWorkingDirectory(), or the current directory if none has been
    explicitly set.

    \sa setWorkingDirectory() QDir::current()
*/
QDir Q3Process::workingDirectory() const
{
    return workingDir;
}

/*!
    Sets \a dir as the working directory for processes. This does not
    affect running processes; only processes that are started
    afterwards are affected.

    Setting the working directory is especially useful for processes
    that try to access files with relative paths.

    \sa workingDirectory() start()
*/
void Q3Process::setWorkingDirectory( const QDir& dir )
{
    workingDir = dir;
}
#endif //QT_NO_DIR

/*!
    Returns the communication required with the process, i.e. some
    combination of the \c Communication flags.

    \sa setCommunication()
*/
int Q3Process::communication() const
{
    return comms;
}

/*!
    Sets \a commFlags as the communication required with the process.

    \a commFlags is a bitwise OR of the flags defined by the \c
    Communication enum.

    The default is \c{Stdin|Stdout|Stderr}.

    \sa communication()
*/
void Q3Process::setCommunication( int commFlags )
{
    comms = commFlags;
}

/*!
    Returns true if the process has exited normally; otherwise returns
    false. This implies that this function returns false if the
    process is still running.

    \sa isRunning() exitStatus() processExited()
*/
bool Q3Process::normalExit() const
{
    // isRunning() has the side effect that it determines the exit status!
    if ( isRunning() )
	return false;
    else
	return exitNormal;
}

/*!
    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.

    If normalExit() 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.

    \sa normalExit() processExited()
*/
int Q3Process::exitStatus() const
{
    // isRunning() has the side effect that it determines the exit status!
    if ( isRunning() )
	return 0;
    else
	return exitStat;
}


/*!
    Reads the data that the process has written to standard output.
    When new data is written to standard output, the class emits the
    signal readyReadStdout().

    If there is no data to read, this function returns a QByteArray of
    size 0: it does not wait until there is something to read.

    \sa readyReadStdout() readLineStdout() readStderr() writeToStdin()
*/
QByteArray Q3Process::readStdout()
{
    if ( readStdoutCalled ) {
	return QByteArray();
    }
    readStdoutCalled = true;
    Q3Membuf *buf = membufStdout();
    readStdoutCalled = false;

    return buf->readAll();
}

/*!
    Reads the data that the process has written to standard error.
    When new data is written to standard error, the class emits the
    signal readyReadStderr().

    If there is no data to read, this function returns a QByteArray of
    size 0: it does not wait until there is something to read.

    \sa readyReadStderr() readLineStderr() readStdout() writeToStdin()
*/
QByteArray Q3Process::readStderr()
{
    if ( readStderrCalled ) {
	return QByteArray();
    }
    readStderrCalled = true;
    Q3Membuf *buf = membufStderr();
    readStderrCalled = false;

    return buf->readAll();
}

/*!
    Reads a line of text from standard output, excluding any trailing
    newline or carriage return characters, and returns it. Returns
    an empty string if canReadLineStdout() returns false.

    By default, the text is interpreted to be in Latin-1 encoding. If you need
    other codecs, you can set a different codec with
    QTextCodec::setCodecForCStrings().

    \sa canReadLineStdout() readyReadStdout() readStdout() readLineStderr()
*/
QString Q3Process::readLineStdout()
{
    QByteArray a( 256 );
    Q3Membuf *buf = membufStdout();
    if ( !buf->scanNewline( &a ) ) {
      if ( !canReadLineStdout() )
	return QString();

      if ( !buf->scanNewline( &a ) )
	return QLatin1String(buf->readAll());
    }

    uint size = a.size();
    buf->consumeBytes( size, 0 );

    // get rid of terminating \n or \r\n
    if ( size>0 && a.at( size - 1 ) == '\n' ) {
      if ( size>1 && a.at( size - 2 ) == '\r' )
	a.chop(2);
      else
	a.chop(1);
    }
    return QString(QString::fromLatin1(a.constData()));
}

/*!
    Reads a line of text from standard error, excluding any trailing
    newline or carriage return characters and returns it. Returns
    an empty string if canReadLineStderr() returns false.

    By default, the text is interpreted to be in Latin-1 encoding. If you need
    other codecs, you can set a different codec with
    QTextCodec::setCodecForCStrings().

    \sa canReadLineStderr() readyReadStderr() readStderr() readLineStdout()
*/
QString Q3Process::readLineStderr()
{
    QByteArray a( 256 );
    Q3Membuf *buf = membufStderr();
    if ( !buf->scanNewline( &a ) ) {
      if ( !canReadLineStderr() )
	return QString();

      if ( !buf->scanNewline( &a ) )
	return QString( QString::fromLatin1( buf->readAll().constData() ) );
    }

    uint size = a.size();
    buf->consumeBytes( size, 0 );

    // get rid of terminating \n or \r\n
    if ( size>0 && a.at( size - 1 ) == '\n' ) {
      if ( size>1 && a.at( size - 2 ) == '\r' )
	a.chop(2);
      else
	a.chop(1);
    }
    return QString( QString::fromLatin1( a.constData() ) );
}

/*!
    \fn bool Q3Process::start( QStringList *env )

    Tries to run a process for the command and arguments that were
    specified with setArguments(), addArgument() 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.

    If \a env is null, then the process is started with the same
    environment as the starting process. If \a env is non-null, then
    the values in the stringlist are interpreted as environment
    setttings of the form \c {key=value} and the process is started in
    these environment settings. For convenience, there is a small
    exception to this rule: under Unix, if \a env does not contain any
    settings for the environment variable \c LD_LIBRARY_PATH, then
    this variable is inherited from the starting process; under
    Windows the same applies for the environment variable \c PATH.

    Returns true if the process could be started; otherwise returns
    false.

    You can write data to the process's standard input with
    writeToStdin(). You can close standard input with closeStdin() and
    you can terminate the process with tryTerminate(), or with kill().

    You can call this function even if you've used this instance to
    create a another process which is still running. In such cases,
    Q3Process 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.)

    \sa launch() closeStdin()
*/

/*!
    \fn void Q3Process::tryTerminate() const

    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 kill() instead.

    The slot returns immediately: it does not wait until the process
    has finished. When the process terminates, the processExited()
    signal is emitted.

    \sa kill() processExited()
*/

/*!
    \fn void Q3Process::kill() const

    Terminates the process. This is not a safe way to end a process
    since the process will not be able to do any cleanup.
    tryTerminate() is safer, but processes can ignore a
    tryTerminate().

    The nice way to end a process and to be sure that it is finished,
    is to do something like this:
    \snippet doc/src/snippets/code/src_qt3support_other_q3process_unix.cpp 0

    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.

    The slot returns immediately: it does not wait until the process
    has finished. When the process terminates, the processExited()
    signal is emitted.

    \sa tryTerminate() processExited()
*/

/*!
    \fn bool Q3Process::isRunning() const

    Returns true if the process is running; otherwise returns false.

    \sa normalExit() exitStatus() processExited()
*/

/*!
    \fn bool Q3Process::canReadLineStdout() const

    Returns true if it's possible to read an entire line of text from
    standard output at this time; otherwise returns false.

    \sa readLineStdout() canReadLineStderr()
*/

/*!
    \fn bool Q3Process::canReadLineStderr() const

    Returns true if it's possible to read an entire line of text from
    standard error at this time; otherwise returns false.

    \sa readLineStderr() canReadLineStdout()
*/

/*!
    \fn void Q3Process::writeToStdin( const QByteArray& buf )

    Writes the data \a buf to the process's standard input. The
    process may or may not read this data.

    This function returns immediately; the Q3Process class might write
    the data at a later point (you must enter the event loop for this
    to occur). When all the data is written to the process, the signal
    wroteToStdin() is emitted. This does not mean that the process
    actually read the data, since this class only detects when it was
    able to write the data to the operating system.

    \sa wroteToStdin() closeStdin() readStdout() readStderr()
*/

/*!
    \fn void Q3Process::closeStdin()

    Closes the process's standard input.

    This function also deletes any pending data that has not been
    written to standard input.

    \sa wroteToStdin()
*/

/*!
    \fn Q3Process::PID Q3Process::processIdentifier()

    Returns platform dependent information about the process. This can
    be used together with platform specific system calls.

    Under Unix the return value is the PID of the process, or -1 if no
    process belongs to this object.

    Under Windows it is a pointer to the \c PROCESS_INFORMATION
    struct, or 0 if no process is belongs to this object.

    Use of this function's return value is likely to be non-portable.
*/

/*!
    \fn void Q3Process::launchFinished()

    This signal is emitted when the process was started with launch().
    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.

    This signal is especially useful if you want to know when you can
    safely delete the Q3Process object when you are not interested in
    reading from standard output or standard error.

    \sa launch() QObject::deleteLater()
*/

/*!
    Runs the process and writes the data \a buf 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.

    If \a env is null, then the process is started with the same
    environment as the starting process. If \a env is non-null, then
    the values in the string list are interpreted as environment
    setttings of the form \c {key=value} and the process is started
    with these environment settings. For convenience, there is a small
    exception to this rule under Unix: if \a env does not contain any
    settings for the environment variable \c LD_LIBRARY_PATH, then
    this variable is inherited from the starting process.

    Returns true if the process could be started; otherwise returns
    false.

    Note that you should not use the slots writeToStdin() and
    closeStdin() on processes started with launch(), since the result
    is not well-defined. If you need these slots, use start() instead.

    The process may or may not read the \a buf data sent to its
    standard input.

    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.)

    The object emits the signal launchFinished() 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.

    \sa start() launchFinished()
*/
bool Q3Process::launch( const QByteArray& buf, QStringList *env )
{
    if ( start( env ) ) {
	if ( !buf.isEmpty() ) {
	    connect( this, SIGNAL(wroteToStdin()),
		    this, SLOT(closeStdinLaunch()) );
	    writeToStdin( buf );
	} else {
	    closeStdin();
	    emit launchFinished();
	}
	return true;
    } else {
	emit launchFinished();
	return false;
    }
}

/*!
    \overload

    The data \a buf is written to standard input with writeToStdin()
    using the QString::local8Bit() representation of the strings.
*/
bool Q3Process::launch( const QString& buf, QStringList *env )
{
    if ( start( env ) ) {
	if ( !buf.isEmpty() ) {
	    connect( this, SIGNAL(wroteToStdin()),
		    this, SLOT(closeStdinLaunch()) );
	    writeToStdin( buf );
	} else {
	    closeStdin();
	    emit launchFinished();
	}
	return true;
    } else {
	emit launchFinished();
	return false;
    }
}

/*
  This private slot is used by the launch() functions to close standard input.
*/
void Q3Process::closeStdinLaunch()
{
    disconnect( this, SIGNAL(wroteToStdin()),
	    this, SLOT(closeStdinLaunch()) );
    closeStdin();
    emit launchFinished();
}


/*!
    \fn void Q3Process::readyReadStdout()

    This signal is emitted when the process has written data to
    standard output. You can read the data with readStdout().

    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.

    \sa readStdout() readLineStdout() readyReadStderr()
*/

/*!
    \fn void Q3Process::readyReadStderr()

    This signal is emitted when the process has written data to
    standard error. You can read the data with readStderr().

    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.

    \sa readStderr() readLineStderr() readyReadStdout()
*/

/*!
    \fn void Q3Process::processExited()

    This signal is emitted when the process has exited.

    \sa isRunning() normalExit() exitStatus() start() launch()
*/

/*!
    \fn void Q3Process::wroteToStdin()

    This signal is emitted if the data sent to standard input (via
    writeToStdin()) 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.

    \sa writeToStdin() closeStdin()
*/


/*!
    \overload

    The string \a buf is handled as text using the
    QString::local8Bit() representation.
*/
void Q3Process::writeToStdin( const QString& buf )
{
    QByteArray tmp = buf.local8Bit();
    tmp.resize( buf.length() );
    writeToStdin( tmp );
}


/*
 * Under Windows the implementation is not so nice: it is not that easy to
 * detect when one of the signals should be emitted; therefore there are some
 * timers that query the information.
 * To keep it a little efficient, use the timers only when they are needed.
 * They are needed, if you are interested in the signals. So use
 * connectNotify() and disconnectNotify() to keep track of your interest.
 */
/*!  \reimp
*/
void Q3Process::connectNotify( const char * signal )
{
#if defined(QT_Q3PROCESS_DEBUG)
    qDebug( "Q3Process::connectNotify(): signal %s has been connected", signal );
#endif
    if ( !ioRedirection )
	if ( qstrcmp( signal, SIGNAL(readyReadStdout()) )==0 ||
		qstrcmp( signal, SIGNAL(readyReadStderr()) )==0
	   ) {
#if defined(QT_Q3PROCESS_DEBUG)
	    qDebug( "Q3Process::connectNotify(): set ioRedirection to true" );
#endif
	    setIoRedirection( true );
	    return;
	}
    if ( !notifyOnExit && qstrcmp( signal, SIGNAL(processExited()) )==0 ) {
#if defined(QT_Q3PROCESS_DEBUG)
	qDebug( "Q3Process::connectNotify(): set notifyOnExit to true" );
#endif
	setNotifyOnExit( true );
	return;
    }
    if ( !wroteToStdinConnected && qstrcmp( signal, SIGNAL(wroteToStdin()) )==0 ) {
#if defined(QT_Q3PROCESS_DEBUG)
	qDebug( "Q3Process::connectNotify(): set wroteToStdinConnected to true" );
#endif
	setWroteStdinConnected( true );
	return;
    }
}

/*!  \reimp
*/
void Q3Process::disconnectNotify( const char * )
{
    if ( ioRedirection &&
	    receivers( SIGNAL(readyReadStdout()) ) ==0 &&
	    receivers( SIGNAL(readyReadStderr()) ) ==0
	    ) {
#if defined(QT_Q3PROCESS_DEBUG)
	qDebug( "Q3Process::disconnectNotify(): set ioRedirection to false" );
#endif
	setIoRedirection( false );
    }
    if ( notifyOnExit && receivers( SIGNAL(processExited()) ) == 0 ) {
#if defined(QT_Q3PROCESS_DEBUG)
	qDebug( "Q3Process::disconnectNotify(): set notifyOnExit to false" );
#endif
	setNotifyOnExit( false );
    }
    if ( wroteToStdinConnected && receivers( SIGNAL(wroteToStdin()) ) == 0 ) {
#if defined(QT_Q3PROCESS_DEBUG)
	qDebug( "Q3Process::disconnectNotify(): set wroteToStdinConnected to false" );
#endif
	setWroteStdinConnected( false );
    }
}

QT_END_NAMESPACE

#endif // QT_NO_PROCESS