File Name Directory Entry
| Offset | Size | Description | Comments |
|---|---|---|---|
| 0 (0x00) | 1 | EntryType | 0xC1 |
| 1 (0x01) | 1 | GeneralSecondaryFlags* | |
| 2 (0x02) | 30 | FileName |
* GeneralSecondaryFlags
| Bits | Size | Attribute | Comments |
|---|---|---|---|
| 0 | 1 | AllocationPossible | Must be 0 |
| 1 | 1 | NoFatChain | Must be 0 |
| 2 | 14 | CustomDefined |
File Name directory entries must immediately follow the Steam Extension directory entry in the number of NameLength/15 rounded up.
The maximum number of File Name entries is 17, each can hold up to 15 Unicode characters and the maximum file name length is 255. Unused portion of FileName field must be set to 0x0000.
Invalid File Name Characters
| Character Code | Character | Description |
|---|---|---|
| 0x0000 - 0x001F | Control codes | |
| 0x0022 | " | Quotation mark |
| 0x002A | * | Asterisk |
| 0x002F | / | Forward slash |
| 0x003A | : | Colon |
| 0x003C | < | Less than |
| 0x003E | > | Greater than |
| 0x003F | ? | Question mark |
| 0x005C | \ | Back slash |
| 0x007C | | | Vertical bar |