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Reading Input With the Open Command

While a layout file is being read and processed, a log file is written. This file contains a record of messages emitted during the conversion. If during a conversion an error or warning message is emitted, a file browsing window containing the log file will appear when the conversion is complete, though this can be suppressed by setting the NoPopUpLog variable. These messages also appear on the prompt line during the conversion. The file browser is a read-only version of the text editor window (see 3.13.2). The log files can be accessed from the Log Files button in the Help Menu.

When reading a layout file, there is a message updated periodically on the prompt line indicating bytes read. One can abort the read with Ctrl-c, and a `y' response to the resulting prompt. It is advisable to clear the cells from the partially read hierarchy from memory with the Clear button in the Cells Listing pop-up.

CGX and GDSII files that have been compressed with the GNU gzip program or have been written in compressed form by Xic can be read in directly, whether or not the file name contains the standard ``.gz'' suffix. Support for compressed files extends to CGX and GDSII only (OASIS files use a different compression methodology).

The header of a GDSII file optionally contains information about fonts, reference libraries, and other things. This information is saved as properties of the top-level cells derived from the file, i.e., those cells that are not used as subcells of another cell in the file. Xic does not use this information, but it will be put back into a GDSII file subsequently written by Xic, as other applications may need this information.

When reading GDSII or OASIS input, Xic will attempt to map the layer number and data type combinations found in the file to existing Xic layers, and if that fails a new Xic layer will be created. This is described in the section on GDSII layer mapping (14.6).

When reading CIF, layer names are matched to those defined in the current technology in a case-insensitive mode. This differs from native and CGX file types, which use case-sensitive matching. Layers found in the file which do not match any in the technology are created, using default parameters.

When a cell is written to disk, it is by default written in the format of origin, though a format change can be coerced in the Save As command by supplying a file extension. Explicit conversions can also be performed with the commands in the Convert Menu.

If a cell is opened for editing that contains empty cells, the user is given the option of deleting these references. If empty cells are found in the hierarchy, a pop-up appears, which allows their deletion. The cell names listed are those that for each mode (electrical and physical) the named cell either does not exist or has no content.

This test can be performed at any time with the !empties command. The test can be suppressed by setting the Skip testing for empty cells check box in the Setup page of the Import Control panel from the Convert Menu, or (equivalently) by setting the NoCheckEmpties variable.


next up previous contents index
Next: Opening New Cells - Up: The Open Button: Open Previous: Input to the Open   Contents   Index
Stephen R. Whiteley 2017-04-09