CGX uses the same long (4-byte) and short (2-byte) integer formats as GDSII, and the same 8-byte floating point format. These are the only numerical data types defined.
A date is stored as 8 bytes, as shown in the following table. These are the same numerical fields as used in GDSII, though the format is different (bytes are used where possible, rather than shorts). The third column gives the value in terms of the members of the tm structure from the C library.
| short | year | tm_year + 1900 |
| byte | month | tm_mon + 1 |
| byte | day | tm_mday |
| byte | hour | tm_hour |
| byte | minute | tm_min |
| byte | second | tm_sec |
| byte | 0 |
Strings are stored in the same manner as in GDSII. The null terminator in not written, however a null byte will be added to strings of odd length, so that record sizes are always even.