ObjcString() provides an universal acces of the label (text)
of any object. The object can be a button, a string, an icon. If
the object has not text, the function does nothing. If a NULL
value is given to newstr parameter, ObjcString() returns the
address of the object text. The text returned can be read or
modified:
printf( "Object i : %s\n", ObjcString( tree, i, NULL), i);
strcpy( ObjcString( tree, i, NULL), "New text");
It is possible to define a new buffer for the object:
char txt[120] = "New text";
ObjcString( tree, i, txt);
ObjcString() should never be used to change the text of an menu
item. For that purpose, use MenuText() instead of ObjcString().
