System Functions

FID( ) Return File Information Descriptor

Format	FID(chan[,ERR=stmtref])   Where:
	chan			Channel or logical file number of the file to return information about.
	stmtref			Program line number or statement label to which to transfer control.
Returns	String, file information descriptor.
Description	The FID( ) function returns a character string containing the file information descriptor for an existing open file. If the file is a device (printer, terminal, etc.), the filename used to open the file will be returned. If the file is a disk file, a file description string is returned. You can make subsequent use of this file description by passing it to a FILE directive to recreate the file. For further information, refer to the File Information Functions Overview and the ProvideX Standard Format for FIB(0) and FID(0). If you are running ProvideX in an emulation mode, the format of the information returned will be changed to reflect the system being emulated.
*Note*	When 'FF' is set to 0 or 3 and the ’PO’ system parameter is switched on, the FID( )
		and FIB( ) functions return the original path used when the file was opened. Also: The FID( ) and FIN( ) format layouts will be changed whenever there is a change to the 'FF' system parameter.
	Determining FID in ProvideX under UNIX By default, ProvideX assigns a unique FID value for each terminal based on the /etc/initab entry for the terminal. Unfortunately, when you use dynamic terminal allocation (e.g., Telnet), each time a user signs off and then signs on, he / she will have a different FID value. There are workarounds, but no one solution works in all instances. If, for security purposes, you use the user_ID rather than terminal_ID, then you can set the file information descriptor in the users profile by inserting the following lines: PVXFID0=desired_FID_val export PVXFID0 As an alternative, you can assign the file information descriptor once in ProvideX, by issuing a SETFID directive to establish a new FID(0) value. If you do not want to use user_IDs but you are using Telnet and PCs, see if there is a host-initiated file transfer you could use to get a file containing the FID value off the PC.   Using WindX, you could open a file on the PC and read it to determine a FID value; e.g.,   0010 OPEN (1) "[wdx]C:\PVXFID" 0020 READ RECORD (1) F$ 0030 CLOSE (1) 0040 SETFID F$   Finally, you could see if the terminal emulator allows you to define values for function keys and has an escape sequence to send the values. Some terminals send a "HEREIS" string on receipt of an ENQ (hex $05$), but this varies from terminal to terminal.   FIB(1) / FID(1)'FF'=1
			Bytes		Description (Total length=22 bytes)
			1,3		$000000$
			4,6		Characters 1-6 of filename
			10,1		File type indicator:
					$00$- Indexed
					$01$- Serial - WindX connected file (any type)
					$02$- Keyed or EFF
					$03$- Open via ISZ= (binary)
					$04$- Program
					$0D$- Directory $0F$- Device
			11,1		External key size
			12,3		Maximum number of records
			15,2		Record size
			17,4		Reserved for future use
			21,2		Characters 7-8 of filename
	FIB(2) / FID(2)'FF'=2
			Bytes		Description (Total length=16 bytes)
			1,6		Characters 1-6 of filename
			7,1		File type indicator:
					$00$- Indexed
					$01$- Serial - WindX connected file (any type)
					$02$- Keyed
					$03$- Open via ISZ= (binary)
					$04$- Program
					$0D$- Directory $0F$- Device
			8,1		External key size
			9,2		Maximum number of records (bytes reversed)
			11,2		Record size (bytes reversed)
			13,4		Not used
	FIB(3) / FID(3)'FF'=3
			Bytes		Description (Total length=9+ bytes)
			1,1		File type indicator:
					$00$ = Indexed
					$01$= Sequential - WindX connected file (any type)
					$02$ = Keyed
					$03$= Opened via ISZ= (Binary)
					$04$ = Program
					$05$ = Directory
					$06$ = BBx Mkeyed (no External Key)
					$07$ = C-Isam
					$0A$= UNIX Pipe
					$0E$ = TCP/IP-Network $0F$= Device/Attached Printer
			2,1		External key size
			3,4		Maximum number of records
			7,2		Record size (bytes reversed)
			9,...		Pathname; e.g.,
					0100 SET_PARAM 'FF'=3 0110 OPEN (30)"SESAME" 0120 LET A$=FID(30) 0130 PRINT A$(9) ->run C:\OTHER\TESTS\SESAME
			1,...		Device name; e.g.,
					0200 SET_PARAM 'FF'=3 0210 OPEN (31)PRINTER$ 0220 B$=FID(31); PRINT B$ ->run LPT1 [Details for files, above (1,1 to 9,...) inapplicable]
	FIB(4) / FID(4)'FF'=4 FID(4) is the same as FID(3) but all serial files return a file type indicator of $03$ for binary. This format is only intended to facilitate program migration to ProvideX.
See Also	FIB( ) Return File Information Block, FIN( ) Return File Information, FILE Directive, 'FF' File format 'PO' Path Original