I need my application to properly zip files in Windows, UNIX, Mac etc. Earlier I was on Zlib 1.2.3 and now migrating to 1.3.1. I have API calls to zipOpenNewFileInZip4 which has a new field versionMadeBy. Has anyone used this successfully in an application across different platforms smoothly. If so could you please guide me on the same
Went through https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
version made by (2 bytes)
4.4.2.1 The upper byte indicates the compatibility of the file
attribute information. If the external file attributes
are compatible with MS-DOS and can be read by PKZIP for
DOS version 2.04g then this value will be zero. If these
attributes are not compatible, then this value will
identify the host system on which the attributes are
compatible. Software can use this information to determine
the line record format for text files etc.
4.4.2.2 The current mappings are:
0 - MS-DOS and OS/2 (FAT / VFAT / FAT32 file systems)
1 - Amiga 2 - OpenVMS
3 - UNIX 4 - VM/CMS
5 - Atari ST 6 - OS/2 H.P.F.S.
7 - Macintosh 8 - Z-System
9 - CP/M 10 - Windows NTFS
11 - MVS (OS/390 - Z/OS) 12 - VSE
13 - Acorn Risc 14 - VFAT
15 - alternate MVS 16 - BeOS
17 - Tandem 18 - OS/400
19 - OS X (Darwin) 20 thru 255 - unused
4.4.2.3 The lower byte indicates the ZIP specification version
(the version of this document) supported by the software
used to encode the file. The value/10 indicates the major
version number, and the value mod 10 is the minor version
number.
I am not completely sure if I understood this documentation
Set the high byte to the operating system that the external attributes (external_fa) come from. If attributes are zero, then just set the operating system to zero.
The low byte would be the originating version of PKZip. I don't think anything ever looks at it, but Section 4.4.3 has a list of PKZip features as a function of the version number. You would likely set it to 45.