The LIBRARY record should be the first data record in the file, and can appear once only.
The flags byte of the record header can be used for a version number, which identifies in some way the remaining data in the file.
The LIBRARY record contains the following fields:
| bytes | field name | purpose |
|---|---|---|
| 8 | munit | machine units |
| 8 | uunit | user units |
| 8 | cdate | library creation date |
| 8 | mdate | library modification date |
| ? | libname | library name string |
The first two fields are double-precision numbers that define the scale factors for the data in the file. These are interpreted in the same way as the similar fields in the header of a GDSII file.
The second two fields represent creation and modification dates for the file content.
A name string for the library follows. Strings are null-byte terminated, and an additional null byte is added if necessary so that the total length is even.