Alternate Entry Name: F.DESC
B: descr = fildes( unit );
C: int fildes(FILE *unit);
FILDES obtains the file descriptor word of an I/O unit. If "unit" is attached to a disk file, FILDES returns a descriptor with the following information.
bits mask meaning ---- ---- ------- 0-5 770000,du Device code (see below) 6-8 007000,du Disposition code (batch) 0 : release 1 : dismount 2 : save 3 : continue 9-17 Unused 18 400000,dl Creation code 0 : file previously existed 1 : file created by open 19 200000,dl 0 : sequential file 1 : random file 20 100000,dl 0 : temporary file 1 : permanent file 21 040000,dl Permanent file dynamically accessed 22-35 037777,dl Size of file in llinks
For other devices, bits 0-8 are as above. See the GCOS manual description of MME GEFADD for a description of the other bits.
The following table gives the device name for each device code. "xxxxxx" means the code is unassigned.
000: xxxxxx .dc355 .dssf .dmca .dddia .dpfep .ddbcs .dhypr 010: .dmtap .dmta7 .dmta9 .dmtm7 .dmtm9 .dmtc7 .dmtc9 .dmtxx 020: .dcr20 .dcr21 .drp24 .dcp20 .dpr41 .dpr30 .dpr21 .dptap 030: .dcons .dscc1 .dcp30 .dcp31 .dcr31 .dpr33 .dpr23 .duncp 040: xxxxxx .dsm1b .dsm1a .dsm2b .dsm2a .dsm1d .dsm2c .dsm2d 050: .dss1b .dss1d .dss1f .dsc1b xxxxxx .dsd1b .dsk1b .dsk1c 060: .ds181 .ds190 .ds191 .ds310 .ds400 .ds450 .ds500 .ds501 070: .dss1a .dss1c .dss1e .dsc1a .dsm1e .dsd1a .dsk1a xxxxxx
For example, a device code of octal 12 in bits 0-5 refers to device ".dmta9" while a device code of octal 65 refers to device ".ds450".
In batch, a device code of 77 (octal) is used by ACC.FILE to indicate a SYSOUT filecode. For a description of the descriptor for a unit attached to a tape in batch, see the GCOS manual under MME GEFADD. A tape is recognized by a device code of the form 1x (octal).
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