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.\" the following conditions:
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.\" The above copyright notice and this permission notice shall be
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.ds tk X Toolkit
.ds xT X Toolkit Intrinsics \- C Language Interface
.ds xI Intrinsics
.ds xW X Toolkit Athena Widgets \- C Language Interface
.ds xL Xlib \- C Language X Interface
.ds xC Inter-Client Communication Conventions Manual
.ds Rn 3
.ds Vn 2.2
.hw XtApp-Add-Input wid-get
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.TH XtAppAddInput 3Xt "Release 6" "X Version 11" "XT FUNCTIONS"
.SH NAME
XtAppAddInput, XtRemoveInput \- register and remove an input source
.SH SYNTAX
XtInputId XtAppAddInput(\fIapp_context\fP, \fIsource\fP, \fIcondition\fP, \
\fIproc\fP, \fIclient_data\fP)
.br
      XtAppContext \fIapp_context\fP;
.br
      int \fIsource\fP;
.br
      XtPointer \fIcondition\fP;
.br
      XtInputCallbackProc \fIproc\fP;
.br
      XtPointer \fIclient_data\fP;
.LP
void XtRemoveInput(\fIid\fP)
.br
      XtInputId \fIid\fP;
.SH ARGUMENTS
.ds Co that identifies the application
.IP \fIapp_context\fP 1i
Specifies the application context \*(Co.
.ds Cd input is available
.IP \fIclient_data\fP 1i
Specifies the argument that is to be passed to the specified procedure
when \*(Cd.
.IP \fIcondition\fP 1i
Specifies the mask that indicates a read, write, or exception condition
or some operating system dependent condition.
.IP \fIid\fP 1i
Specifies the ID returned from the corresponding
.ZN XtAppAddInput
call.
.ds Pr \ to be called when input is available
.IP \fIproc\fP 1i
Specifies the procedure that is\*(Pr.
.IP \fIsource\fP 1i
Specifies the source file descriptor on a UNIX-based system
or other operating system dependent device specification.
.SH DESCRIPTION
The
.ZN XtAppAddInput
function registers with the \*(xI read routine a new source of events,
which is usually file input but can also be file output.
Note that file should be loosely interpreted to mean any sink 
or source of data.
.ZN XtAppAddInput
also specifies the conditions under which the source can generate events.
When input is pending on this source,
the callback procedure is called.
.LP
The legal values for the condition argument are operating-system dependent.
On a UNIX-based system,
the condition is some union of
.ZN XtInputReadMask ,
.ZN XtInputWriteMask ,
and
.ZN XtInputExceptMask .
The
.ZN XtRemoveInput
function causes the \*(xI read routine to stop watching for input
from the input source.
.SH "SEE ALSO"
XtAppAddTimeOut(3Xt),XtAppAddSignal(3Xt)
.br
\fI\*(xT\fP
.br
\fI\*(xL\fP
.LP
.SH "BUGS"
In ANSI C it is necessary to cast the condition to an XtPointer, e.g.:
.RS 4
.br
XtAppAddInput(app_context, 
.RS 4
.br
source,
.br
.B (XtPointer)
XtInputReadMask | XtInputWriteMask,
.br
proc,
.br
client_data);
.RE
