Re: [bug-gnulib] fwriteerror() interface

[Paul Eggert]

In the latest patch, those three gotos confused me.  Part of the
confusion is due to uses like 'if (fflush (fp))' which are of course
valid but which I find a bit hard to read at first.  Also, the
comment's "contents is" is not quite grammatical, and the comment is a
bit overconfident about getting the "same errno".

How about this (untested) patch to make the code a bit more readable?


2006-04-24  Paul Eggert  <address@hidden>

        * fwriteerror.c (fwriteerror): Rewrite to avoid gotos.

*** fwriteerror.c       Mon Apr 24 10:32:45 2006
--- /tmp/fwriteerror.c  Mon Apr 24 11:15:01 2006
*************** fwriteerror (FILE *fp)
*** 46,72 ****
  
    if (ferror (fp))
      {
-       if (fflush (fp))
-       goto close_preserving_errno; /* errno is set here */
        /* The stream had an error earlier, but its errno was lost.  If the
!        error was not temporary, we can get the same errno by writing and
         flushing one more byte.  We can do so because at this point the
!        stream's contents is garbage anyway.  */
!       if (fputc ('\0', fp) == EOF)
!       goto close_preserving_errno; /* errno is set here */
!       if (fflush (fp))
!       goto close_preserving_errno; /* errno is set here */
!       /* Give up on errno.  */
!       errno = 0;
!      close_preserving_errno:
!       /* There's an error.  Nevertheless call fclose(fp), for consistency
!        with the other cases.  */
!       {
!       int saved_errno = errno;
!       fclose (fp);
!       errno = saved_errno;
!       return -1;
!       }
      }
  
    /* If we are closing stdout, don't attempt to do it later again.  */
--- 46,65 ----
  
    if (ferror (fp))
      {
        /* The stream had an error earlier, but its errno was lost.  If the
!        error was not temporary, we can usually get a useful errno by
!        flushing the file, or, if that doesn't work, by writing and
         flushing one more byte.  We can do so because at this point the
!        stream contains garbage anyway.  */
!       int saved_errno =
!         (fflush (fp) != 0 || fputc ('\0', fp) == EOF || fflush (fp) != 0
!        ? errno
!        : 0);
! 
!       /* Close the file, for consistency with the other cases.  */
!       fclose (fp);
!       errno = saved_errno;
!       return -1;
      }
  
    /* If we are closing stdout, don't attempt to do it later again.  */