XmSpinBoxValidatePosition(library call)XmSpinBoxValidatePosition(library call)NAMEXmSpinBoxValidatePosition — translate the current value of the speci‐
fied XmSpinBox child into a valid position
SYNOPSIS
#include <Xm/SpinBox.h>
int XmSpinBoxValidatePosition(
Widget textfield,
int *position);
DESCRIPTION
The XmSpinBoxValidatePosition function is a utility that can be used by
applications wanting to implement a policy for tracking user modifica‐
tions to editable XmSpinBox children of type XmNUMERIC. The specifics
of when and how the user's modifications take effect is left up to the
application.
text_field
The text_field argument specifies the widget ID of the child
of the XmSpinBox that is being modified. The requirement on
text_field is that it holds the accessTextual trait (already
a requirement for children of XmSpinBox). This way, XmSpinBox
can extract the string out of the text_field widget (even if
it is not an XmTextField).
position The location pointed to by the position argument is assigned
the result of the translation done by XmSpinBoxValidatePosi‐
tion. XmSpinBoxValidatePosition first checks to make sure
this is an XmNUMERIC XmSpinBox child. If it is not, XSmpin‐
BoxValidatePosition sets position to the current position and
returns XmCURRENT_VALUE.
XmSpinBoxValidatePosition attempts to translate the input string to a
floating point number. If this translation fails, XmSpinBoxValidatePo‐
sition sets position to the current position and returns XmCUR‐
RENT_VALUE.
XmSpinBoxValidatePosition converts the floating point number to an
integer using the XmNdecimalPoints resource. Extra decimal places are
truncated. The resulting integer is range checked to make sure it falls
within the valid range defined by XmNminimumValue and XmNmaximumValue
inclusive. If the input falls outside this range, XmSpinBoxValidatePo‐
sition sets position to the nearest limit and returns either XmMINI‐
MUM_VALUE or XmMAXIMUM_VALUE.
Finally, XmSpinBoxValidatePosition checks the integer to make sure it
belongs to the series defined by XmNminimumValue ... XmNminumumValue +
((n - 1) * XmNincrementlValue). If the integer does not belong to this
series, XmSpinBoxValidatePosition sets position to the nearest element
which is less than or equal to the integer and returns XmINCRE‐
MENT_VALUE.
Otherwise, XmSpinBoxValidatePosition assigns the integer to position
and returns XmVALID_VALUE.
RETURN VALUE
The XmSpinBoxValidatePosition function returns the status of the vali‐
dation. The set of possible values returned is as follows:
XmCURRENT_VALUE
Cannot convert, returning current position_value.
XmMINIMUM_VALUE
Less than min.
XmMAXIMUM_VALUE
More than max.
XmINCREMENT_VALUE
Not on increment.
XmVALID_VALUE
Okay.
EXAMPLES
This first example demonstrates how the XmSpinBoxValidatePosition func‐
tion could be used from inside an XmNmodifyVerifyCallback callback
installed on the XmSpinBox or the XmSimpleSpinBox:
/*
* Install a callback on a spin box arrow press.
*/
XtAddCallback(sb, XmNmodifyVerifyCallback, ModifyVerifyCB, NULL);
XtAddCallback(simple_sb, XmNmodifyVerifyCallback, ModifyVerifyCB, NULL);
with the callback doing:
void ModifyVerifyCB(widget, call_data, client_data) {
XmSpinBoxCallbackStruct *cbs = (XmSpinBoxCallbackStruct*) call_data;
int position;
Widget textual = NULL;
if (XtIsSubclass(w, xmSimpleSpinBoxWidgetClass))
{
Arg args[1];
XtSetArg(args[0], XmNtextField, &textual);
XtGetValues(w, args, 1);
}
else if (XtIsSubclass(w, xmSpinBoxWidgetClass))
textual = cbs->widget;
else
textual = (Widget) NULL;
...
if (XmSpinBoxValidatePosition(textual, &position) == XmCURRENT_VALUE)
XBell(XtDisplay(w), 0);
else
cbs->position = position;
}
This second example demonstrates how the XmSpinBoxValidatePosition
function could be used from inside an XmNactivateCallback callback
installed on the TextField child of the XmSpinBox:
/*
* Install a callback on a spin box arrow press.
*/
XtAddCallback(tf, XmNactivateCallback, ModifyVerifyChildCB, NULL);
with the callback doing:
void ModifyVerifyChildCB(widget, call_data, client_data) {
int position;
Widget textual = widget;
Arg args[1];
if (XmSpinBoxValidatePosition (textual, &position) == XmCURRENT_VALUE)
XBell(XtDisplay(widget), 0);
/* Set the position constraint resource of the textfield */
XtSetArg(args[0], XmNposition, position);
XtSetValues(textual, args, 1);
}
SEE ALSOXmSpinBox(3), XmCreateSpinBox(3)
XmSpinBoxValidatePosition(library call)
