XtSetArg(), XtMergeArgLists() - set and merge ArgLists
XtSetArg (Arg arg, String name, XtArgVal value)
ArgList XtMergeArgLists (ArgList args1, Cardinal num_args1,
ArgList args2, Cardinal num_args2)
The XtSetArg(3) function is usually used in a highly stylized manner to minimize the probability of making a mistake; for example:
Arg args[20];
int n;
n = 0;
XtSetArg(args[n], XtNheight, 100);n++;
XtSetArg(args[n], XtNwidth, 200);n++;
XtSetValues(widget, args, n);
Alternatively, an application can statically declare the argument list and use XtNumber(3):
static Args args[] = {
{XtNheight, (XtArgVal) 100},
{XtNwidth, (XtArgVal) 200},
};
XtSetValues(Widget, args, XtNumber(args));
Note that you should not use auto-increment or auto-decrement within the first argument to XtSetArg(3). XtSetArg(3) can be implemented as a macro that dereferences the first argument twice.
The XtMergeArgLists(3) function allocates enough storage to hold the combined ArgList structures and copies them into it. Note that it does not check for duplicate entries. When it is no longer needed, free the returned storage by using XtFree.
XtOffset()
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface