projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 46c6eca3 KT |
1 | .pa 1 |
| 2 | .he 'ARCHIVE (V)'3/15/72'ARCHIVE (V)' | |
| 3 | .ti 0 | |
| 4 | NAME archive (library) file format | |
| 5 | .sp | |
| 6 | .ti 0 | |
| 7 | DESCRIPTION The | |
| 8 | archive command ar\b\b__ is used to combine several files into | |
| 9 | one. | |
| 10 | Archives are used mainly as libraries to be searched | |
| 11 | by the link-editor ld\b\b__. | |
| 12 | ||
| 13 | A file produced by ar\b\b__ | |
| 14 | has a "magic number" at the start, | |
| 15 | followed by the constituent files, each preceded by a file header. | |
| 16 | The magic number is | |
| 17 | 177555(8) | |
| 18 | (it was chosen to be unlikely to occur anywhere else). | |
| 19 | The header of each file is 16 bytes long: | |
| 20 | ||
| 21 | .in +5 | |
| 22 | .ti -3 | |
| 23 | 0-7 | |
| 24 | .br | |
| 25 | file name, null padded on the right | |
| 26 | ||
| 27 | .ti -3 | |
| 28 | 8-11 | |
| 29 | .br | |
| 30 | Modification time of the file | |
| 31 | ||
| 32 | .ti -3 | |
| 33 | 12 | |
| 34 | .br | |
| 35 | User ID of file owner | |
| 36 | ||
| 37 | .ti -3 | |
| 38 | 13 | |
| 39 | .br | |
| 40 | file mode | |
| 41 | ||
| 42 | .ti -3 | |
| 43 | 14-15 | |
| 44 | .br | |
| 45 | file size | |
| 46 | ||
| 47 | .in -5 | |
| 48 | If the file is an odd number of bytes long, it is padded | |
| 49 | with a null byte, but the size in the header is correct. | |
| 50 | ||
| 51 | Notice there is no provision for empty areas in an archive | |
| 52 | file. | |
| 53 | .sp | |
| 54 | .ti 0 | |
| 55 | SEE ALSO ar\b\b__, ld\b\b__ |