Re: 'fflush' test failure on Cygwin

[Bruno Haible]

Eric Blake wrote:
> Meanwhile, I'm checking in this.
> 
> 2007-04-25  Eric Blake  <address@hidden>
> 
>       * lib/fpurge.c (includes): Use stdlib.h for free.
>       * tests/test-fflush.c (main): Also test fflush-fseeko.

Thanks. Addendum:

2007-04-26  Bruno Haible  <address@hidden>

        * modules/fflush-tests (Depends-on): Add fseeko.

*** modules/fflush-tests        17 Apr 2007 03:38:08 -0000      1.3
--- modules/fflush-tests        26 Apr 2007 08:17:48 -0000
***************
*** 2,7 ****
--- 2,8 ----
  tests/test-fflush.c
  
  Depends-on:
+ fseeko
  
  configure.ac:
  

With your additions, the test now fails again on MacOS X. It is because
the stream caches the fd's position, hence the lseek() calls confuse
ftell(). This fixes it:

2007-04-26  Bruno Haible  <address@hidden>

        * tests/test-fflush.c (main): Also check the ftell result after
        fflush and fseek/fseeko.
        * lib/fflush.c (rpl_fflush): For BSD implementations, update the
        file descriptor position cache in the stream.
        * lib/fseeko.c (rpl_fseeko): Likewise.

*** tests/test-fflush.c 25 Apr 2007 13:22:15 -0000      1.2
--- tests/test-fflush.c 26 Apr 2007 09:19:52 -0000
***************
*** 74,79 ****
--- 74,86 ----
        unlink ("test-fflush.txt");
        return 1;
      }
+   if (ftell (f) != 5)
+     {
+       fputs ("ftell result is wrong after fseek.\n", stderr);
+       fclose (f);
+       unlink ("test-fflush.txt");
+       return 1;
+     }
    /* Check that file reading resumes at correct location.  */
    if (fgetc (f) != '6')
      {
***************
*** 106,111 ****
--- 113,125 ----
        unlink ("test-fflush.txt");
        return 1;
      }
+   if (ftell (f) != 6)
+     {
+       fputs ("ftell result is wrong after fseek.\n", stderr);
+       fclose (f);
+       unlink ("test-fflush.txt");
+       return 1;
+     }
    /* Check that file reading resumes at correct location.  */
    if (fgetc (f) != '7')
      {
*** lib/fflush.c        23 Apr 2007 12:49:50 -0000      1.4
--- lib/fflush.c        26 Apr 2007 09:19:52 -0000
***************
*** 58,64 ****
       semantics of fpurge are now appropriate to clear the buffer.  To
       avoid losing data, the lseek is also necessary.  */
    result = fpurge (stream);
!   if (result == 0 && lseek (fileno (stream), pos, SEEK_SET) == -1)
      return EOF;
!   return result;
  }
--- 58,71 ----
       semantics of fpurge are now appropriate to clear the buffer.  To
       avoid losing data, the lseek is also necessary.  */
    result = fpurge (stream);
!   if (result != 0)
!     return result;
!   pos = lseek (fileno (stream), pos, SEEK_SET);
!   if (pos == -1)
      return EOF;
! #if defined __sferror               /* FreeBSD, NetBSD, OpenBSD, MacOS X, 
Cygwin */
!   stream->_offset = pos;
!   stream->_flags |= __SOFF;
! #endif
!   return 0;
  }
*** lib/fseeko.c        25 Apr 2007 09:14:49 -0000      1.1
--- lib/fseeko.c        26 Apr 2007 09:19:52 -0000
***************
*** 66,72 ****
  #else
    #error "Please port gnulib fseeko.c to your platform! Look at the code in 
fpurge.c, then report this to bug-gnulib."
  #endif
!     return (lseek (fileno (fp), offset, whence) == (off_t)(-1) ? -1 : 0);
    else
      return fseeko (fp, offset, whence);
  }
--- 66,89 ----
  #else
    #error "Please port gnulib fseeko.c to your platform! Look at the code in 
fpurge.c, then report this to bug-gnulib."
  #endif
!     {
!       off_t pos = lseek (fileno (fp), offset, whence);
!       if (pos == -1)
!       {
! #if defined __sferror               /* FreeBSD, NetBSD, OpenBSD, MacOS X, 
Cygwin */
!         fp->_flags &= ~__SOFF;
! #endif
!         return -1;
!       }
!       else
!       {
! #if defined __sferror               /* FreeBSD, NetBSD, OpenBSD, MacOS X, 
Cygwin */
!         fp->_offset = pos;
!         fp->_flags |= __SOFF;
! #endif
!         return 0;
!       }
!     }
    else
      return fseeko (fp, offset, whence);
  }


Bruno