PENSTONE@QUCDNEE1.BITNET.UUCP (01/13/87)
< How does one determine from inside a program whether an existing disk file
< (FORM="UNFORMATTED") is RECORDTYPE="VARIABLE" .....
There is a C function stat() that returns some information about
a file. It puts it into a structure which is described in stat.h of the
C library. The values to look for in the "record format" and
"record attributes" values are described in fab.h. You can identify
the values FAB$C_FIX or FAB$C_VAR in the st_fab_rfm field of the structure
filled by the stat() call, and the record attributes in the st_fab_rat field.
If that doesn't work, then you will have to use the dreaded FAB and RAB
calls provided in RMS ! (Not really as terrifying as they look; an
afternoon's reading of the RMS manuals will usually suffice...they work
well from C, but are a bit more of a pain in FORTRAN because of the difficulty
of creating structures.)
Sid Penstone
Dept. Of Electrical Engineering,
Queen's University, Kingston, Ontario, Canada
PENSTONE@QUCDNEE1.BITNETgarry@TCGOULD.TN.CORNELL.EDU.UUCP (01/15/87)
In a recent article Sid Penstone said: >< How does one determine from inside a program whether an existing disk file >< (FORM="UNFORMATTED") is RECORDTYPE="VARIABLE" ..... > > There is a C function stat() that returns some information about >a file. .............. You can identify >the values FAB$C_FIX or FAB$C_VAR in the st_fab_rfm field of the structure >... I'm sorry; this won't work. As I explained privately to the original poster, "Segented" records are a concept known *only* to Fortran. They consist of variable records with a couple extra bytes tacked on; the entire rest of the universe just sees plain variable records and isn't aware that there's extra information in there. BTW, FAB$C_FIX refers to "fixed-length" records. Is something different. (But I'm glad to know stat() returns actual RMS info - could be handy!) garry wiegand (garry%cadif-oak@cu-arpa.cs.cornell.edu)