Comparison of labels can lead to false differences when comparing cells read from different file formats, since label bounding boxes are not well defined across file format conversion.
Property comparisons are available only in per-cell object mode. Property lists of cells, instances, and objects can be filtered by property number and compared. Only the property lists of otherwise identical instances or objects will be compared. Property comparison is turned off by default, but can be enabled with the -p option.
If u is given, custom filtering will be applied. There are separate filters available for properties of cells, instances, and objects, for both physical and electrical comparisons. Custom filtering can be set up through the Custom Property Filter Setup panel, or by directly setting the corresponding variables. See the description of the panel in 14.13.3 for complete information.
If neither of these letters appear, default filtering is applied. For physical data, the default filtering action is no filtering. For electrical data, filtering is applied to cell and instance properties, and object properties are ignored, so that difference reporting applies to user-defined properties only.
Properties are compared by number and string. In the output file, property comparison result lines are all in comment form (with `#' as the first character) so that they will be ignored if the file is subsequently processed with the !diffcells command. Property comparison results consist of a string indicating the cell, instance, or object containing the properties. If an instance or object, this is common to both input sources. Following this are listings of properties found in one source and not the other. Properties that are identical in the two sources are not listed.