backspace/endfile combination bug

[Toon Moene]

[ CC'd to David M. Gay, author of f2c and the f2c run time library,
  which is used by g77 ]

grhoden wrote:

> It appears that the file positioning gets screwed up when initiating a
> backspace command followed by an endfile command.  This is for
> gcc-2.95.1 running on Mandrake linux 6.0.  Attached is a bit of code
> that recreates the problem.
> 
> This code when compiled with g77 -o testit test.f gives the following
> errors to xterm:
> 
> fmt: end of file
> apparent state: unit 9 named ./test.txt
> last format: (A80)
> lately reading sequential formatted external IO
> Aborted (core dumped)

[ Program source: ]

>       program test
>       character chk2*80
>       open(9,file='./test.txt')
>       write(9,*) 'This is a test of the scratch file'
>       write(9,*) 'Writing a second record'
>       backspace (9)
>       endfile (9)
>       print *,'executed endfile command'
>       rewind (9)
>       print *,'executed rewind command'
>       read(9,'(A80)') chk2
> c      read(9,'(A80)') chk2
> c      read(9,'(A80)') chk2
>       print *,'executed read command'
>       print *, chk2
>       close (9)
>       stop
>       end

I could reproduce this behaviour with both g77/gcc-2.95.2 and the latest
f2c (downloaded today) on Red Hat Linux 5.2.

According to my reading of the Standard, this sequence of file
operations is allowed.

Unfortunately, I didn't succeed in tracking down the error.

-- 
Toon Moene (toon@moene.indiv.nluug.nl)
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
Phone: +31 346 214290; Fax: +31 346 214286
GNU Fortran: http://gcc.gnu.org/onlinedocs/g77_news.html