Strange behavior with string passing in fortran 77 (gfortran,g77,f77)

[aschaeffer]

Hi,

I've attached a small program extracted from a large program I'm trying to compile in Linux 64 (Ubuntu 9.10). Basically it is a wrapper function to open a file where a directory prefix is automatically added. This is legacy code from an old project (with thousands of lines). When a quoted string is passed to the subroutine, additional text is added to the variable. However, when passed as a string in a variable, this does not occur. Is passing a quoted string in this manner (Test 1 below) not a legal manner in fortran 77? The program, the compiler instruction, and the output I get is in the comments at the end. Thanks for any help, Andrew.
------------------------------------------------------------
C Output from Public domain Ratfor, version 1.01
program ami3d
character*100 testfile
print *,' Test 1:'
print *, ' Testing openfile for quoted string'
print *,kar('testfile123')
call openfile(12,'testfile123')

print *,' '
print *,' Test 2:'
print *,' Testing openfile for passed variable'
testfile="testfile123"
print *,kar(testfile)
call openfile(12,testfile)
end


function kar(string)
character*100 string
kk=100
ii=ichar(string(kk:kk))
800 if((ii.gt.126 .or. ii.lt.33) .and. kk.gt.1)then
kk=kk-1
ii=ichar(string(kk:kk))
goto 800
endif
801 continue
kar=kk
return
end


subroutine openfile(nfile,fname)
! common /opname/ fitdir
character*100 fitdir, fname
write(6,'(a,a,a)') '-',fname(1:kar(fname)),'-'
! open(nfile,file=fitdir(1:kar(fitdir))//fname(1:kar(fname)))
return
end


! compile line:
![aschaeff@triton aschaeff]$ gfortran -std=legacy testfilename.f -o amitest
!
! The output from running this program
![aschaeff@triton aschaeff]$ amitest
! Test 1:
! Testing openfile for quoted string
! 74
!-testfile123
! Test 2: Testing openfile for passed variable(a,a,a)--
!
! Test 2:
! Testing openfile for passed variable
! 11
!-testfile123-
![aschaeff@triton aschaeff]$

 

[mikrom]

The problem is not in Fortran but in your function kar(). I didn' see the sence why you compute everytime

ii=ichar(string(100:100))

when your string has less then 100 characters.
I modified the function kar() so, that it first computes the length of the string and this gives you the same result for both cases:

[COLOR=#0000ff]!  Output from Public domain Ratfor, version 1.01[/color]
      [COLOR=#a020f0]program[/color] ami3d
      [COLOR=#2e8b57][b]character[/b][/color][COLOR=#804040][b]*[/b][/color][COLOR=#ff00ff]100[/color] testfile
      [COLOR=#804040][b]print[/b][/color] [COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]' Test 1:'[/color]
      [COLOR=#804040][b]print[/b][/color] [COLOR=#804040][b]*[/b][/color], [COLOR=#ff00ff]'  Testing openfile for quoted string'[/color]
      [COLOR=#804040][b]print[/b][/color] [COLOR=#804040][b]*[/b][/color],kar([COLOR=#ff00ff]'testfile123'[/color])

      [COLOR=#804040][b]print[/b][/color] [COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]' Test 2:'[/color]
      [COLOR=#804040][b]print[/b][/color] [COLOR=#804040][b]*[/b][/color],[COLOR=#ff00ff]'  Testing openfile for passed variable'[/color]
      testfile[COLOR=#804040][b]=[/b][/color][COLOR=#ff00ff]"testfile123"[/color]
      [COLOR=#804040][b]print[/b][/color] [COLOR=#804040][b]*[/b][/color], kar(testfile)
      [COLOR=#a020f0]end program[/color] ami3d


      [COLOR=#a020f0]function[/color] kar(string)
      [COLOR=#2e8b57][b]character[/b][/color]([COLOR=#804040][b]*[/b][/color]) string
      kk[COLOR=#804040][b]=[/b][/color][COLOR=#008080]LEN_TRIM[/color](STRING)
      ii[COLOR=#804040][b]=[/b][/color][COLOR=#008080]ichar[/color](string(kk:kk))
[COLOR=#6a5acd]800[/color]   [COLOR=#804040][b]if[/b][/color]((ii[COLOR=#804040][b].gt.[/b][/color][COLOR=#ff00ff]126[/color] [COLOR=#804040][b].or.[/b][/color] ii[COLOR=#804040][b].lt.[/b][/color][COLOR=#ff00ff]33[/color]) [COLOR=#804040][b].and.[/b][/color] kk[COLOR=#804040][b].gt.[/b][/color][COLOR=#ff00ff]1[/color])[COLOR=#804040][b]then[/b][/color]
        kk[COLOR=#804040][b]=[/b][/color]kk[COLOR=#804040][b]-[/b][/color][COLOR=#ff00ff]1[/color]
        ii[COLOR=#804040][b]=[/b][/color][COLOR=#008080]ichar[/color](string(kk:kk))
        [COLOR=#804040][b]goto[/b][/color] [COLOR=#ff00ff]800[/color]
      [COLOR=#804040][b]endif[/b][/color]
[COLOR=#6a5acd]801[/color]   [COLOR=#804040][b]continue[/b][/color]
      kar[COLOR=#804040][b]=[/b][/color]kk
      [COLOR=#804040][b]return[/b][/color]
      [COLOR=#a020f0]end function[/color] kar

Output:

$ g95 -g aschaeffer.f95 -o aschaeffer

$ aschaeffer
  Test 1:
   Testing openfile for quoted string
 11
  Test 2:
   Testing openfile for passed variable
 11

 

[aschaeffer]

mikrom, thanks.

That works for me as well. Was the strange output I was getting related to passing a string that was not 100 characters in length to a variable that was expecting a string of 100 characters?

 

[mikrom]

I think, YES