janee@ima.isc.com (Jane Eisenstein) (06/12/91)
I've been following the discussion on how to obtain permanent file references. I now know how to obtain the file's volume name and and directory ID. How do I use them to open the file? In particular, how do I use them to open a file on an unmounted volume whose absolute pathname is > 255 characters long? Thanks, Jane Eisenstein
keith@Apple.COM (Keith Rollin) (06/12/91)
In article <1991Jun11.195057.20315@ima.isc.com> janee@ima.isc.com (Jane Eisenstein) writes: > >I've been following the discussion on how to obtain permanent file >references. I now know how to obtain the file's volume name and >and directory ID. How do I use them to open the file? In particular, >how do I use them to open a file on an unmounted volume whose absolute >pathname is > 255 characters long? Most often, one gets a reference to a file through StandardFile. Under 6.0.x, you get a vRefNum (which is really a working directory ID) and a file name. You can turn the WD into a real vRefNum and dirID by calling GetWDInfo. Under 7.0, you can make the Standard File call that already returns a real vRefNum and dirID. To get the name of a volume if you have its vRefNum, call GetVInfo with the vRefNum and a pointer to a string buffer. To turn the name back into a vRefNum later, you should be able to make another GetVInfo call. To access the file once you have the vRefNum and dirID again, simply stuff those values into the right parameters of whatever call you need to make. For instance, HOpen explicitly takes a vRefNum, dirID, and file name as parameters. The length of the absolute pathname is irrelevant, as you never need to generate it. -- ------------------------------------------------------------------------------ Keith Rollin --- Apple Computer, Inc. INTERNET: keith@apple.com UUCP: {decwrl, hoptoad, nsc, sun, amdahl}!apple!keith "But where the senses fail us, reason must step in." - Galileo
llama@eleazar.dartmouth.edu (Joe Francis) (06/13/91)
janee@ima.isc.com (Jane Eisenstein) writes: >I've been following the discussion on how to obtain permanent file >references. I now know how to obtain the file's volume name and >and directory ID. How do I use them to open the file? In particular, >how do I use them to open a file on an unmounted volume whose absolute >pathname is > 255 characters long? OK. The following is shortened code to do that. I'm skipping the part about mounting volumes (hiden in the imaginary function "MountViewerVolume", which also return the name of the mounted volume). If you are trying to mount AppleShare volumes, let me know and I can post on that subject. This is consensed code - no error checking, let the buyer beware: #include <Types.h> #include <Files.h> void OpenFile(StringPtr fileName, long dirID) /*open file filename in directory dirID on whatever */ /*volume MountViewerVolume mystically mounts. */ { short vRefNum,sourceRefnum = 0; Str255 sourceName; short wdRefNum; HParamBlockRec pb; MountViewerVolume((char*)(&sourceName)); /* mount volume */ SetVol((StringPtr)(&sourceName),0); /* make it current */ GetVol((StringPtr)(&sourceName),&sourceRefnum); /* get it's vol refnum */ OpenWD(sourceRefnum,dirID,0,&wdRefNum); /* make working dir */ pb.fileParam.ioCompletion = 0L; /* set up param block */ pb.fileParam.ioVRefNum = sourceRefnum; pb.fileParam.ioDirID = dirID; pb.fileParam.ioNamePtr = fileName; pb.fileParam.ioPermssn = fsCurPerm; pb.fileParam.ioMisc = 0L; PBOpen(&pb,false); /* open file */ } ---------------------------------------------------------------------------- "Read My Lips: No Nude Texans!" - George Bush clearing up a misunderstanding
Edward.Rice@p4214.f421.n109.z1.FidoNet.Org (Edward Rice) (06/18/91)
JE> I've been following the discussion on how to obtain permanent file
JE> references. I now know how to obtain the file's volume name and
JE> and directory ID. How do I use them to open the file? In particular,
JE> how do I use them to open a file on an unmounted volume whose absolute
JE> pathname is > 255 characters long?
Inside Mac again...
FUNCTION PBOpen (paramBlock: ParmBlkPtr; async: BOOLEAN) : OSErr;
Parameter block
Q> 12 ioCompletion pointer
<Q 16 ioResult word
Q> 18 ioNamePtr pointer
Q> 22 ioVRefNum word
<Q 24 ioRefNum word
Q> 26 ioVersNum byte
Q> 27 ioPermssn byte
Q> 28 ioMisc pointer
PBOpen creates an access path to the file having the name pointed to by ioNamePtr (and on flat volumes, the version number ioVersNum) on the volume specified by ioVRefNum. A path reference number is returned in ioRefNum.
IOMisc either points to a portion of memory (522 bytes) to be used as the access pathUs buffer, or is NIL if you want the volume buffer to be used instead.
Of course, on S/7, you can use aliases to shorten pathnames, if you're trying to handle the ">255 character pathname" in that environment.
* Origin: "It's still in beta testing," Tom said pointedly. (1:109/421.4214)dorner@pequod.cso.uiuc.edu (Steve Dorner) (06/18/91)
In article <677239715.1@blkcat.FidoNet> Edward.Rice@p4214.f421.n109.z1.FidoNet.Org (Edward Rice) writes: >IOMisc either points to a portion of memory (522 bytes) to be used as the >access pathUs buffer, or is NIL if you want the volume buffer to be used >instead. Beware. Failure to set this field properly will lead to very unpleasant and mysterious results on SE's and earlier. I think newer ROMS either ignore the value or do some sort of sanity checking on it. I speak from personal experience... -- Steve Dorner, U of Illinois Computing Services Office Internet: s-dorner@uiuc.edu UUCP: uunet!uiucuxc!uiuc.edu!s-dorner