wang@math.ufl.edu (04/08/91)
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
As you can see, this character function routine just returns the
character string for a cursor's position on the screen according to
its two arguments. The above program works just fine on VAX/VMS
machines but crashes on UNIX machines (specifically, SunSparc
workstations). The error messages I got when I ran it on a SunSparc
workstation are listed below:
iio: [-1] end of file
lately: writing sequential formatted internal IO
part of last string: |
IOT trap
Can you offer a sulotion to fix the problem?
Thanks a lot in advance!wang@math.ufl.edu (04/08/91)
I guess my character function subprogram is ok, but I cannot just call it directly in the PRINT statement (under Unix, of course). For example, it would work if my main program is writen like this: CHARACTER*8 cursor,string,cls*4 cls = CHAR(27)//'[2J' i = 5 j = 35 string = cursor(i,j) PRINT *,cls,string,'I am here!' END This would, in my opinion, miss the point of conveniency of function subprogram. My question is this: Why can't we call "cursor" directly in the PRINT statement under Sun Fortran?
system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson)) (04/11/91)
In article <1991Apr7.211058.25661@math.ufl.edu> wang@math.ufl.edu writes: >This would, in my opinion, miss the point of conveniency of function >subprogram. My question is this: Why can't we call "cursor" directly >in the PRINT statement under Sun Fortran? This is mentioned in some FORTRAN manuals as a limitation - you are in effect trying to use the I/O libraries recursively in the original program, and some I/O libraries are not re-entrant in this way. Of course, FORTRAN-77 doesn't have to provide recursion. -- Mike Peterson, System Administrator, U/Toronto Department of Chemistry E-mail: system@alchemy.chem.utoronto.ca Tel: (416) 978-7094 Fax: (416) 978-8775
vsnyder@jato.jpl.nasa.gov (Van Snyder) (04/12/91)
In article <1991Apr11.162324.9004@alchemy.chem.utoronto.ca> system@alchemy.chem.utoronto.ca (System Admin (Mike Peterson)) writes: >In article <1991Apr7.211058.25661@math.ufl.edu> wang@math.ufl.edu writes: >>This would, in my opinion, miss the point of conveniency of function >>subprogram. My question is this: Why can't we call "cursor" directly >>in the PRINT statement under Sun Fortran? > >This is mentioned in some FORTRAN manuals as a limitation - you are in >effect trying to use the I/O libraries recursively in the original >program, and some I/O libraries are not re-entrant in this way. >Of course, FORTRAN-77 doesn't have to provide recursion. It also violates section 12.11 of the standard: "A function must not be referenced within an expression appearing anywhere in an input/output list if such a reference causes an input/output statement to be executed." -- vsnyder@jato.Jpl.Nasa.Gov ames!elroy!jato!vsnyder vsnyder@jato.uucp
trevor@ccc.govt.nz (04/16/91)
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...) I do know you can't use any sort of direct cursor addressing when writing for GEM; you have to use the appropriate GEM VDI or AES call. I know this doesn't HELP much, but I hope it might explain a little. Trevor Ingham, Systems Programmer, Christchurch City Council, New Zealand. trevor@ccc.govt.nz
trevor@ccc.govt.nz (04/17/91)
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