docs/latex/wx/process.tex

   1 \section{\class{wxProcess}}\label{wxprocess}
   2
   3 The objects of this class are used in conjunction with the
   4 \helpref{wxExecute}{wxexecute} function. When a wxProcess object is passed to
   5 wxExecute(), its \helpref{OnTerminate()}{wxprocessonterminate} virtual method
   6 is called when the process terminates. This allows the program to be
   7 (asynchronously) notified about the process termination and also retrieve its
   8 exit status which is unavailable from wxExecute() in the case of
   9 asynchronous execution.
  10
  11 Please note that if the process termination notification is processed by the
  12 parent, it is responsible for deleting the wxProcess object which sent it.
  13 However, if it is not processed, the object will delete itself and so the
  14 library users should only delete those objects whose notifications have been
  15 processed (and call \helpref{Detach()}{wxprocessdetach} for others).
  16
  17 wxProcess also supports IO redirection of the child process. For this, you have
  18 to call its \helpref{Redirect}{wxprocessredirect} method before passing it to
  19 \helpref{wxExecute}{wxexecute}. If the child process was launched successfully,
  20 \helpref{GetInputStream}{wxprocessgetinputstream},
  21 \helpref{GetOutputStream}{wxprocessgetoutputstream} and
  22 \helpref{GetErrorStream}{wxprocessgeterrorstream} can then be used to retrieve
  23 the streams corresponding to the child process stdandard output, input and
  24 error output respectively.
  25
  26 \wxheading{Derived from}
  27
  28 \helpref{wxEvtHandler}{wxevthandler}
  29
  30 \wxheading{Include files}
  31
  32 <wx/process.h>
  33
  34 \wxheading{See also}
  35
  36 \helpref{wxExecute}{wxexecute}\\
  37 \helpref{exec sample}{sampleexec}
  38
  39 \latexignore{\rtfignore{\wxheading{Members}}}
  40
  41 \membersection{wxProcess::wxProcess}\label{wxprocessconstr}
  42
  43 \func{}{wxProcess}{\param{wxEvtHandler *}{ parent = NULL}, \param{int}{ id = -1}}
  44
  45 Constructs a process object. {\it id} is only used in the case you want to
  46 use wxWindows events. It identifies this object, or another window that will
  47 receive the event.
  48
  49 If the {\it parent} parameter is different from NULL, it will receive
  50 a wxEVT\_END\_PROCESS notification event (you should insert EVT\_END\_PROCESS
  51 macro in the event table of the parent to handle it) with the given {\it id}.
  52
  53 \wxheading{Parameters}
  54
  55 \docparam{parent}{The event handler parent.}
  56
  57 \docparam{id}{id of an event.}
  58
  59 \membersection{wxProcess::\destruct{wxProcess}}
  60
  61 \func{}{\destruct{wxProcess}}{\void}
  62
  63 Destroys the wxProcess object.
  64
  65 \membersection{wxProcess::CloseOutput}\label{wxprocesscloseoutput}
  66
  67 \func{void}{CloseOutput}{\void}
  68
  69 Closes the output stream (the one connected to the stdin of the child
  70 process). This function can be used to indicate to the child process that
  71 there is no more data to be read - usually, a filter program will only
  72 terminate when the input stream is closed.
  73
  74 \membersection{wxProcess::Detach}\label{wxprocessdetach}
  75
  76 \func{void}{Detach}{\void}
  77
  78 Normally, a wxProcess object is deleted by its parent when it receives the
  79 notification about the process termination. However, it might happen that the
  80 parent object is destroyed before the external process is terminated (e.g. a
  81 window from which this external process was launched is closed by the user)
  82 and in this case it {\bf should not delete} the wxProcess object, but
  83 {\bf should call Detach()} instead. After the wxProcess object is detached
  84 from its parent, no notification events will be sent to the parent and the
  85 object will delete itself upon reception of the process termination
  86 notification.
  87
  88 \membersection{wxProcess::GetErrorStream}\label{wxprocessgeterrorstream}
  89
  90 \constfunc{wxInputStream* }{GetErrorStream}{\void}
  91
  92 Returns an input stream which corresponds to the standard error output (stderr)
  93 of the child process.
  94
  95 \membersection{wxProcess::GetInputStream}\label{wxprocessgetinputstream}
  96
  97 \constfunc{wxInputStream* }{GetInputStream}{\void}
  98
  99 It returns an input stream corresponding to the standard output stream of the
 100 subprocess. If it is NULL, you have not turned on the redirection.
 101 See \helpref{wxProcess::Redirect}{wxprocessredirect}.
 102
 103 \membersection{wxProcess::GetOutputStream}\label{wxprocessgetoutputstream}
 104
 105 \constfunc{wxOutputStream* }{GetOutputStream}{\void}
 106
 107 It returns an output stream correspoding to the input stream of the subprocess.
 108 If it is NULL, you have not turned on the redirection.
 109 See \helpref{wxProcess::Redirect}{wxprocessredirect}.
 110
 111 \membersection{wxProcess::Kill}\label{wxprocesskill}
 112
 113 \func{static wxKillError}{Kill}{\param{int}{ pid}, \param{wxSignal}{ signal = wxSIGNONE}}
 114
 115 Send the specified signal to the given process. Possible signal values are:
 116
 117 \begin{verbatim}
 118 enum wxSignal
 119 {
 120     wxSIGNONE = 0,  // verify if the process exists under Unix
 121     wxSIGHUP,
 122     wxSIGINT,
 123     wxSIGQUIT,
 124     wxSIGILL,
 125     wxSIGTRAP,
 126     wxSIGABRT,
 127     wxSIGEMT,
 128     wxSIGFPE,
 129     wxSIGKILL,      // forcefully kill, dangerous!
 130     wxSIGBUS,
 131     wxSIGSEGV,
 132     wxSIGSYS,
 133     wxSIGPIPE,
 134     wxSIGALRM,
 135     wxSIGTERM       // terminate the process gently
 136 };
 137 \end{verbatim}
 138
 139 {\tt wxSIGNONE}, {\tt wxSIGKILL} and {\tt wxSIGTERM} have the same meaning
 140 under both Unix and Windows but all the other signals are equivalent to
 141 {\tt wxSIGTERM} under Windows.
 142
 143 Returns the element of {\tt wxKillError} enum:
 144
 145 \begin{verbatim}
 146 enum wxKillError
 147 {
 148     wxKILL_OK,              // no error
 149     wxKILL_BAD_SIGNAL,      // no such signal
 150     wxKILL_ACCESS_DENIED,   // permission denied
 151     wxKILL_NO_PROCESS,      // no such process
 152     wxKILL_ERROR            // another, unspecified error
 153 };
 154 \end{verbatim}
 155
 156 \wxheading{See also}
 157
 158 \helpref{wxProcess::Exists}{wxprocessexists},\rtfsp
 159 \helpref{wxKill}{wxkill},\rtfsp
 160 \helpref{Exec sample}{sampleexec}
 161
 162 \membersection{wxProcess::Kill}\label{wxprocessexists}
 163
 164 \func{static bool}{Exists}{\param{int}{ pid}}
 165
 166 Returns {\tt TRUE} if the given process exists in the system.
 167
 168 \wxheading{See also}
 169
 170 \helpref{wxProcess::Kill}{wxprocesskill},\rtfsp
 171 \helpref{Exec sample}{sampleexec}
 172
 173 \membersection{wxProcess::OnTerminate}\label{wxprocessonterminate}
 174
 175 \constfunc{void}{OnTerminate}{\param{int}{ pid}, \param{int}{ status}}
 176
 177 It is called when the process with the pid {\it pid} finishes.
 178 It raises a wxWindows event when it isn't overridden.
 179
 180 \docparam{pid}{The pid of the process which has just terminated.}
 181
 182 \docparam{status}{The exit code of the process.}
 183
 184 \membersection{wxProcess::Redirect}\label{wxprocessredirect}
 185
 186 \func{void}{Redirect}{\void}
 187
 188 Turns on redirection. wxExecute will try to open a couple of pipes
 189 to catch the subprocess stdio. The caught input stream is returned by
 190 GetOutputStream() as a non-seekable stream. The caught output stream is returned
 191 by GetInputStream() as a non-seekable stream.
 192