← go to soft exit
IF (ID. EQ. IHX) GO TO 
← go to hard exit
HTML-IMAGE.nr 0C 0 HTML-IMAGE-END.lf 1 - HTML-IMAGE.nr 0C 0 HTML-IMAGE-END.ce SPECPR User Communication
All user input is to the integer array IOPCON dimensioned 80 in /LBL4/ common. The I/O is by a read statement with an 80A1 format. All numbers and characters are decoded from this array.
The actual decoding is perfomed by the subroutine WJFREN (for wedge free input routine). The call is: CALL WJFREN (I, X, IL) where I is the column number pointer (array index value) in IOPCON (1 to 80), X is a real number returned, and IL is a letter or character returned. I is intitially set before the first call (usually to 1, the beginning of the line) and then WJFREN updates the pointer. If a number is encountered, X is set to that number, if a character is encountered the character is returned in IL. If a number and a character are back-to-back (no spaces) then both the number and the character are returned in X and IL, respectively by one call to WJFREN. If a number is followed by a space and then a character, the first call to WJFREN returns the number in X and sets IL to an integer zero then the second call will return the character (with X set to zero). Thus number inputs are essentially automatically checked for illegal characters (positive numbers do not require a plus sign - plus signs are returned as characters). If a negative sign is followed by a blank or a character it is returned as character (thus a negative sign followed by a blank then a number will not be returned as a negative number).
The following is an example of how SPECPR might decode 2 numbers. Also, if the user types an E or X, the program exits.
SUBROUTINE TEST (TEST1, TEST2)
DATA IHE,IHX /1HE, 1HX/
1 CALL CRTIN User input.
I=1 start scan at column 1.
CALL WJFREN (I, X, IL)
IF (I. LT. 80) GO to 10 If ≥ 80, no input.
9 CALL WHAT (I) flag error.
GO TO 1 start over.
10 IF ((IL. EQ. IHE). exist of requested.
1OR. (IL. EQ. IHX))
2RETURN
IF (IL. NE. 0) error: character
1GO TO 9 encountered.
TEST1=X First number.
CALL WJFREN (I,X,IL) Get second number.
IF (I. GE. 80) GO TO 9 no second number.
IF (IL. NE. 0) GO TO 9 error: character
encountered.
TEST2=X second number.
RETURN
END
Subroutine WHAT writes a question mark on the terminal and a carrot (^) sign at the value of I which is indicative of where the error occured. If no characters were input (I≥80), no carrot sign is printed and a question mark is printed in column 1.
This is a lot more work than just a FORTRAN read statement, but the input is totally checked for errors, the range of the numbers (if they have limits or conditions) can be checked and flaged and characters can be input on the same line for other controls (either mixed with the number or in place of numbers). This allows for maximum flexibility for the user to control the program with a minimum of typing and reading and answering question.
SPECPR Spectral Data File I/O
The following pages show code examples for reading and writing specpr data records involving spectra and the header to the data.
All file status and control parameters are stored in 5 common blocks. User communication (CRT I/O) needs the /LBL4/ common block (132 words).
To read a spectrum from the disc or tape files you must write a prompting message and then the 9 FORTRAN statements given on the next pages. If you want to give the user the soft or hard exit option (type E or X) you must test the variable: ID for equaling a Hollerith E or X after the WJFREN call (statement 3). This is done in SPECPR using a data statement:
DATA IHE, IHX /1HE, 1HX/
Then test ID after the WJFREN call:
IF (ID. EQ. IHE) GO TO
All control of tapes, I/O error checking, error messages, protection and file pointer update are performed by REDFIL.
To write a spectrum data record to disc or tape you can follow the 11 FORTRAN statements given on the following pages (a prompting message is also needed) or you can call the subroutine MTHWRT which is used by the math routines to decode where the user wants to write the data. This routine does all the prompting and user input error handling. This latter method only requires 2 lines of FORTRAN to write the results. All file control and updates are performed by these routines as similar to that done in reading a file.
SPECPR I/O
Minimum Procedure for Reading a Spectral Data File
Comments
1 CALL CRTIN read line: 80 characters
2 I = 1 begin scan at column 1
3 CALL WJFREN (I, X, ID) scan for letter code: ID
4 CALL WJFREN (I, X, IL) scan for file number: X
5 IRECNO = X set record number
6 CALL DEVOK (4, ID, check to see if device is OK
IRECNO, LUN, IER) to read:
4=access code-4 is all but
starpacks
ID=file letter code
LUN=Logical unit number
decoded from ID.
DEVOK will print IER:→error code
any appropriate =0 → OK
error messages. =1 → bad status
=2 → protection
violation
=3 → both 1 and 2
7 IF (IER. NE 0) GO TO 
Branch if error
8 CALL REDFIL (IRECNO, read data
LUN, IER)
9 IF (IER. NE 0) GO Branch if error (any
TO 
I/O errors will be
explained to the user)
SPECPR I/O
Minimum Procedure fo Writing a Spectral Data File
Comments
1 CALL CRTIN read line: 80 characters
2 I = 1 begin scan at column 1
3 CALL WJFREN (I, X, ID) scan for letter code: ID
4 CALL WJFREN (I, X, IL) scan for record number: X
5 IRECNO = X set record number
6 CALL DEVLUN (4, ID, LUN) get logical unit #: LUN
7 CALL DEVSTA (LUN, ISTA, check status: write errors
IER, IPRT) OK: IER=0
get protection: IPRT
8 IF ((IRECNO. EQ. 0). set default record #
AND. (IPRT. GE. 0))
IRECNO = IPRT + 1
9 IF (IPRT. LT. -1) read only device
GO TO 
10 IF ((IPRT. NE. -1). illegal record #
AND. (IRECNO. NE.
IPRT + 1)) GO TO
11 CALL WRIFIL (IRECNO, write data
LUN, IER)
SPECPR I/O
Writing Spectral Data File (con’t)
Shorter Alternative
1 CALL MTHWRT (IGO, LUN, performs step 1-10 and
IRECNO, IPRODP) and includes prompting
and error messages
IGO=0: OK
=150: error
=110: soft exit
=1101: hard exit
2 CALL WRIFIL (IRECNO, Note: IPRODP is "Production
LUN, IER) processing" = automatic write
to device V at file #=IPRTV
+1 (V protection +1)
SPECPR common for file I/O and Restart
Common Blocks Needed for File Control
/LABELF/ file pointers & status 11 words
/LBL7/ control variables,
spare title array (20 words) 35 words
/LBLG/ band normalization limits, channels
in use 5 words
/LBLVOL/ file names 201 words
/LBLPRT/ protection 6 words
Other common blocks saved in restart file
/LBL6/ device in use 2 words
/LBL4/ CRT I/O arrays, tape names, min
and max for CRT plot vert &
horiz axes 130 words
/LABEL3/ RA, Dec, latitude of obs, airmass 11 words
/INFO/ user information page print flags 12 words
The following common block are partially saved/restored in rstart
/CMD/ data for the freeformat input routine 167 words
/LBL3/ error array, control flags 516 words
/LABEL1/ all except data 512 words
/HPTRM/ HP terminal status & graphics
control 30 words
BLANK data, titles 1044 words
total 2682 words
DEVLUN
After decoding a file ID letter and record number, find the logical unit number by calling
DEVLUN (I, IDLETR, LUN)
where the file letter ID Logical unit number of the device which devices are valid:
= 0 : all units (V, W, D, U, Y, and S)
= 4 : all but S
for normal Math Operations and Special Functions the variable I is 4. The variables I and IDLETR do not have to be variables in the calling program
e.g. CALL DEVLUN (4, 1HV, LUN)
Note: LUN must be a variable.
DEVSTA
After the file logical unit number has been found, the device status must be checked (e.g. not assigned, etc.). The call is
CALL DEVSTA (LUN, ISTA, I, IPRT)
where logical unit number returned status condition:
device online, record pointer to the value of ISTA
assigned to "/dev/null"
illegal device (not LUN of V, U, D, W, Y, or S)
= 0 : return without printing
= 1 : print message reflecting above status
Device Protection
read/write anywhere. (no protection)
protected. Read up to protection number, write only to protection number +1.
read-only device. (up to absolute value of the protection number).
The variable ISTA and IPRT must be variables in the calling program.
After the routines DEVLUN and DEVSTA have been called, check the value of ISTA to be sure it is greater than zero and the file number being accessed is allowed by the protection (IPRT).
Subroutine RSTART (IC)
RSTART sets up the SPECPR files and protections for restarting the program at the same condition as when SPECPR was last terminated (from Program Operations).
Store the current parameters for a future restart.
Restart: Recall the parameters and assign and open all the files and devices.
Restart: Recall the parameters but don’t assign and open any files. If 32 is added to the above the the arrays dataa, datac and error are not saved or restored