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 standard output, input and
  24 error output respectively.
  25
  26 \perlnote{In wxPerl this class has an additional {\tt Destroy} method,
  27 for explicit destruction.}
  28
  29 \wxheading{Derived from}
  30
  31 \helpref{wxEvtHandler}{wxevthandler}
  32
  33 \wxheading{Include files}
  34
  35 <wx/process.h>
  36
  37 \wxheading{See also}
  38
  39 \helpref{wxExecute}{wxexecute}\\
  40 \helpref{exec sample}{sampleexec}
  41
  42 \latexignore{\rtfignore{\wxheading{Members}}}
  43
  44 \membersection{wxProcess::wxProcess}\label{wxprocessconstr}
  45
  46 \func{}{wxProcess}{\param{wxEvtHandler *}{ parent = NULL}, \param{int}{ id = -1}}
  47
  48 Constructs a process object. {\it id} is only used in the case you want to
  49 use wxWindows events. It identifies this object, or another window that will
  50 receive the event.
  51
  52 If the {\it parent} parameter is different from NULL, it will receive
  53 a wxEVT\_END\_PROCESS notification event (you should insert EVT\_END\_PROCESS
  54 macro in the event table of the parent to handle it) with the given {\it id}.
  55
  56 \wxheading{Parameters}
  57
  58 \docparam{parent}{The event handler parent.}
  59
  60 \docparam{id}{id of an event.}
  61
  62 \membersection{wxProcess::\destruct{wxProcess}}
  63
  64 \func{}{\destruct{wxProcess}}{\void}
  65
  66 Destroys the wxProcess object.
  67
  68 \membersection{wxProcess::CloseOutput}\label{wxprocesscloseoutput}
  69
  70 \func{void}{CloseOutput}{\void}
  71
  72 Closes the output stream (the one connected to the stdin of the child
  73 process). This function can be used to indicate to the child process that
  74 there is no more data to be read - usually, a filter program will only
  75 terminate when the input stream is closed.
  76
  77 \membersection{wxProcess::Detach}\label{wxprocessdetach}
  78
  79 \func{void}{Detach}{\void}
  80
  81 Normally, a wxProcess object is deleted by its parent when it receives the
  82 notification about the process termination. However, it might happen that the
  83 parent object is destroyed before the external process is terminated (e.g. a
  84 window from which this external process was launched is closed by the user)
  85 and in this case it {\bf should not delete} the wxProcess object, but
  86 {\bf should call Detach()} instead. After the wxProcess object is detached
  87 from its parent, no notification events will be sent to the parent and the
  88 object will delete itself upon reception of the process termination
  89 notification.
  90
  91 \membersection{wxProcess::GetErrorStream}\label{wxprocessgeterrorstream}
  92
  93 \constfunc{wxInputStream* }{GetErrorStream}{\void}
  94
  95 Returns an input stream which corresponds to the standard error output (stderr)
  96 of the child process.
  97
  98 \membersection{wxProcess::GetInputStream}\label{wxprocessgetinputstream}
  99
 100 \constfunc{wxInputStream* }{GetInputStream}{\void}
 101
 102 It returns an input stream corresponding to the standard output stream of the
 103 subprocess. If it is NULL, you have not turned on the redirection.
 104 See \helpref{wxProcess::Redirect}{wxprocessredirect}.
 105
 106 \membersection{wxProcess::GetOutputStream}\label{wxprocessgetoutputstream}
 107
 108 \constfunc{wxOutputStream* }{GetOutputStream}{\void}
 109
 110 It returns an output stream correspoding to the input stream of the subprocess.
 111 If it is NULL, you have not turned on the redirection.
 112 See \helpref{wxProcess::Redirect}{wxprocessredirect}.
 113
 114 \membersection{wxProcess::Kill}\label{wxprocesskill}
 115
 116 \func{static wxKillError}{Kill}{\param{int}{ pid}, \param{wxSignal}{ signal = wxSIGNONE}}
 117
 118 Send the specified signal to the given process. Possible signal values are:
 119
 120 \begin{verbatim}
 121 enum wxSignal
 122 {
 123     wxSIGNONE = 0,  // verify if the process exists under Unix
 124     wxSIGHUP,
 125     wxSIGINT,
 126     wxSIGQUIT,
 127     wxSIGILL,
 128     wxSIGTRAP,
 129     wxSIGABRT,
 130     wxSIGEMT,
 131     wxSIGFPE,
 132     wxSIGKILL,      // forcefully kill, dangerous!
 133     wxSIGBUS,
 134     wxSIGSEGV,
 135     wxSIGSYS,
 136     wxSIGPIPE,
 137     wxSIGALRM,
 138     wxSIGTERM       // terminate the process gently
 139 };
 140 \end{verbatim}
 141
 142 {\tt wxSIGNONE}, {\tt wxSIGKILL} and {\tt wxSIGTERM} have the same meaning
 143 under both Unix and Windows but all the other signals are equivalent to
 144 {\tt wxSIGTERM} under Windows.
 145
 146 Returns the element of {\tt wxKillError} enum:
 147
 148 \begin{verbatim}
 149 enum wxKillError
 150 {
 151     wxKILL_OK,              // no error
 152     wxKILL_BAD_SIGNAL,      // no such signal
 153     wxKILL_ACCESS_DENIED,   // permission denied
 154     wxKILL_NO_PROCESS,      // no such process
 155     wxKILL_ERROR            // another, unspecified error
 156 };
 157 \end{verbatim}
 158
 159 \wxheading{See also}
 160
 161 \helpref{wxProcess::Exists}{wxprocessexists},\rtfsp
 162 \helpref{wxKill}{wxkill},\rtfsp
 163 \helpref{Exec sample}{sampleexec}
 164
 165 \membersection{wxProcess::Exists}\label{wxprocessexists}
 166
 167 \func{static bool}{Exists}{\param{int}{ pid}}
 168
 169 Returns {\tt TRUE} if the given process exists in the system.
 170
 171 \wxheading{See also}
 172
 173 \helpref{wxProcess::Kill}{wxprocesskill},\rtfsp
 174 \helpref{Exec sample}{sampleexec}
 175
 176 \membersection{wxProcess::OnTerminate}\label{wxprocessonterminate}
 177
 178 \constfunc{void}{OnTerminate}{\param{int}{ pid}, \param{int}{ status}}
 179
 180 It is called when the process with the pid {\it pid} finishes.
 181 It raises a wxWindows event when it isn't overridden.
 182
 183 \docparam{pid}{The pid of the process which has just terminated.}
 184
 185 \docparam{status}{The exit code of the process.}
 186
 187 \membersection{wxProcess::Redirect}\label{wxprocessredirect}
 188
 189 \func{void}{Redirect}{\void}
 190
 191 Turns on redirection. wxExecute will try to open a couple of pipes
 192 to catch the subprocess stdio. The caught input stream is returned by
 193 GetOutputStream() as a non-seekable stream. The caught output stream is returned
 194 by GetInputStream() as a non-seekable stream.
 195