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Newsgroups: comp.lang.fortran
Subject: Re: Re: character function subprogram
Message-ID: <1991Apr17.131857.214@ccc.govt.nz>
From: trevor@ccc.govt.nz
Date: 17 Apr 91 13:18:56 NZDT
References: <1991Apr7.200854.25446@math.ufl.edu> <1991Apr15.140403.210@ccc.govt.nz>
Organization: Christchurch City Council, New Zealand.
Lines: 72

In article <1991Apr15.140403.210@ccc.govt.nz>, trevor@ccc.govt.nz writes:
> In article <1991Apr7.200854.25446@math.ufl.edu>, wang@math.ufl.edu writes:
>> Can anyboby explain to me why the following FORTRAN character function
>> subprogram works under VAX/VMS, but doesn't work under unix (SunOS 4.1.1,
>> Sun Fortran 1.3)? 
>> 
>>       CHARACTER*8 cursor,cls*4
>>       cls = CHAR(27)//'[2J'
>>       i   = 5
>>       j   = 35
>>       PRINT *,cls,cursor(i,j),'I am here!'
>>       END
>> 
>>       CHARACTER FUNCTION cursor*8(row,col)
>>       CHARACTER*1 esc,c1*2,c2*2
>>       INTEGER row,col
>>       esc = CHAR(27)
>>       WRITE(c1,'(i2.2)') row
>>       WRITE(c2,'(i2.2)') col
>>       cursor = esc//'['//c1//';'//c2//'H'
>>       RETURN
>>       END
>> 
>> (Unix messages deleted...)
>> 
> 
> I think the main problem is that direct screen addressing; direct cursor
> positioning are system-dependent: even worse, they are peripheral-dependent.
> The program quoted writes an output string which contains an ANSI
> device-control escape sequence. It should work fine if sent to a DEC VT100,
> VT200, VT300 terminal (or any other VDU which emulates a DEC ANSI CRT or 
> accepts ANSI device control) by a system which passes on the escape sequence
> uncorrupted, but it won't work right on a VT52 or a printer, I think the 
> screen control sequences for HP terminals were different (but it's a looong 
> time since I programmed for one) and I'd be surprised if it did work under 
> Unix on a Sun.
> Direct cursor addressing isn't standard Fortran. (Fortran carriage-controls 
> for printers IS standard, but we have one printer that doesn't recognise 
> them...)
>

Sorry. I'd missed the function reference in the PRINT statement (I read it
as an array reference - oops). Thank you to those of you who have been patient
enough to point out the error of my ways.

I think what I was talking about was:
 
       CHARACTER*8 cursor,cls*4
       character*8 string
       cls = CHAR(27)//'[2J'
       i   = 5
       j   = 35
       string = cursor(i,j)
       PRINT *,cls,string,'I am here!'
       END
 
       CHARACTER FUNCTION cursor*8(row,col)
       CHARACTER*1 esc,c1*2,c2*2
       INTEGER row,col
       esc = CHAR(27)
       WRITE(c1,'(i2.2)') row
       WRITE(c2,'(i2.2)') col
       cursor = esc//'['//c1//';'//c2//'H'
       RETURN
       END
			which just leaves the (system-dependent) device
controls to be fixed. 

I *will* try to pay closer attention in future...

 Trevor Ingham, Systems Programmer, Christchurch City Council, New Zealand.
 trevor@ccc.govt.nz