Table of Contents

## Name

XtAppAddInput, XtRemoveInput - register and remove an input source

## Syntax

XtInputId XtAppAddInput(XtAppContext app_context, int source,
  XtPointer condition, XtInputCallbackProc proc, XtPointer client_data);
void XtRemoveInput(XtInputId id);

## Arguments

app_context
  Specifies the application context that identifies the application.
client_data
  Specifies the argument that is to be passed to the specified procedure when input is available.
condition
  Specifies the mask that indicates a read, write, or exception condition or some operating system dependent condition.
id
  Specifies the ID returned from the corresponding XtAppAddInput call.
proc
  Specifies the procedure that is to be called when input is available.
source
  Specifies the source file descriptor on a UNIX-based system or other operating system dependent device specification.

## Description

The XtAppAddInput function registers with the Intrinsics 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. XtAppAddInput also specifies the conditions under which the source can generate events. When input is pending on this source, the callback procedure is called.

The legal values for the condition argument are operating-system dependent. On a UNIX-based system, the condition is some union of XtInputReadMask, XtInputWriteMask, and XtInputExceptMask. The XtRemoveInput function causes the Intrinsics read routine to stop watching for input from the input source.

## See Also

XtAppAddTimeOut(3Xt) ,XtAppAddSignal(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface

## Bugs

In ANSI C it is necessary to cast the condition to an XtPointer, e.g.:

> XtAppAddInput(app_context,

> > source,
> > (XtPointer) (XtInputReadMask | XtInputWriteMask),
> > proc,
> > client_data);

> Table of Contents

> - Name
> - Syntax
> - Arguments
> - Description
> - See Also
> - Bugs