jtn@potomac.ads.com (John T. Nelson) (03/12/91)
Oh THIS is interesting. There's a function to opn resources (RFopen()) but there's no function to actually close the resource file! At least none that I can find offhand. Am I expected to use FSclose? If I do that won't that also close the data fork which I MIGHT want open? See, I'd like to open both forks independently and close them independently. The program I'm working on compares the contents of resource forks byte by byte. Interestingly enough, files that are EXECT duplicates of each other (call them fileA and fileB) have differing resource contents, at least according to this program that I've written. Will resource forks ALWAYS be different between files even when I've used COMMAND-D to duplicate them from the finder? Their data forks are identical, that's no problem. But their resource forks are always different. Wierd. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= ORGANIZATION: Advanced Decision Systems GEOGRAPHIC: Arlington, VA UUCP: kzin!speaker@mimsy.umd.edu INTERNET: jtn@potomac.ads.com SPOKEN: Dark Hacker PHONE: (703) 243-1611 The Mythos of Dark Hacker: "Controlled by the sinister and shadowy "suits" Dark Hacker now employs the tools of computer science to free himself from the suit's will. By day he is a lackey... but at night when the city sleeps he becomes.... DARK HACKER!" =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) (03/12/91)
The way I understand it, _OpenRF returns an i/o refnum for the resource fork, the same way _Open returns one for the data fork. You can use this resource fork refnum with all the regular file i/o calls (_Read, _Write, _SetEOF etc), and when you've finished with it, you close it with _Close. If you open the data fork at the same time, you'll get a different refnum, which you can use with the same calls, as though it were a completely separate file. No conflict. As for differences between resource forks of supposedly identical files, it could just be because part of the first 256 bytes of the resource fork is "reserved for system use" (see Inside Mac pgs I-128 to I-129). Maybe something gets written here during the copying process--who knows? Lawrence D'Oliveiro fone: +64-71-562-889 Computer Services Dept fax: +64-71-384-066 University of Waikato electric mail: ldo@waikato.ac.nz Hamilton, New Zealand 37^ 47' 26" S, 175^ 19' 7" E, GMT+13:00